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Ab-initio molecular dynamics is useless (7/21/2024)
(Fig.1) Unrealistic quantum mechanical Pauli exchange energy lacking real (exchange) force stops physicists from treating atoms realistically forever.
The current science has already reached a deadend with No more benefits or scientific progress, as shown in the recent ineffective COVID-19 vaccines and "gas stove ban" which unreasonable restriction would just incovenience our life by politicizing "science" without developing really useful energy-efficient technologies.
And the current 100-year-old illusory "successful quantum mechanics" is proven completely useless for curing many devastating diseases such as cancers, Alzheimer and HIV..
The current dead-end fictional quantum mechanical theory forces scientists to just hype and create fictitious scientific targets such as parallel-world quantum computers.
Quantum mechanics relies on paradoxical and unrealistic exchange energy expressed unphysical Pauli antisymmetric wavefunction to describe (fictitious) molecular covalent bond and Pauli repulsive contact force.
↑ This unphysical quantum mechanical Pauli antisymmetric wavefunction requires every single electron to always exist in all different atoms unrealistically, which lead to the current impractical mainstream quantum mechanical model such as the one-pseudo-electron density functional theory (= DFT ) model and time-consuming molecular dynamical simulation, which stops our scientific development forever.
(Fig.1') Constructing practical buildings and cars does Not need the time-consuming calculation of total energies of all atoms and electrons constituting buildings and cars ! ← But useless quantum mechanical methods need this meaningless process that stops science progress.
When we construct some practical buildings, cars, planes and machines, all we need to do is measure the shape, size and basic property of each component and putting them together to build bigger structures.
It is completely unnecessary and a waste of time to calculate the meaningless "total energies" of all atoms and electrons composing each building and car to construct them.
In the same way, if we want to construct some molecular nano-devices, all we need to do is measure the shape, size (= estimated by the region exerting contact force or Pauli repulsion ) and basic property (= electromagnetic force or tendency to cause some particular chemical reactions ) of each atom and molecule using the current atomic force or scanning tunnel microscopes. We do Not need to waste too much time in calculating the meaningless total energies (= including extremely large inner and outer electrons's ionization energies ) of all molecules.
But the unphysical obsolete quantum mechanical atomic model can Not omit this meaningless, time-consuming processes of conducting the preposterous calculations of "total energies" of all atoms and electrons composing the whole target molecule or protein to estimate some (fictitious) physical properties.
Because the quantum mechanics peremptorily demands to rely on the unphysical exchange energies with No exchange force or No physical meaning to explain the molecular attractive bond energies and Pauli repulsive energies ( this p.11, this p.9-10, this p.5-upper, this p.8-lower ).
↑ Getting these unphysical exchange energies allegedly caused by the fictitious electron's kinetic energy change ( this-introduction-3rd-paragraph ) needs the meaningless time-consuming calculation of total energy (= which includes the fictitious kinetic energy exchange energy ) of all atoms and electrons expressed as the tedious antisymmetric wavefunctions or Slater determinants.
But thinking commonsensically, it is unrealistic and impossible to calculate the extremely large atomic total energies including inner and outer electrons' big ionization energies just for estimating very weak intermolecular interactions such as van der Waals energy that plays a major role in causing enzymatic reactions.
The energies of the atomic inner electrons usually exceed 1000 eV even in the medium-sized atoms.
The intermolecular van der Waals force (= ~0.01 eV ) and hydrogen bond (= ~ 0.1 eV ) playing important roles in protein and biological reactions are far weaker than the inner electrons' binding energies (= ~ 1000 eV ).Quantum mechanics can Not solve any multi-electron Schrödinger equations except for the simplest one-electron hydrogen, which calculated energy results happen to be equal to the Bohr's realistic atomic model.
So quantum mechanics needs to artificially choose fake solutions or trial wavefunctions called basis sets and adjust many free parameters to illegitimately obtain the (fake) total energy by integrating those chosen wavefunctions instead of legitimately solving unsolvable Schrödinger equations.
↑ These calculations of integrating Schrödinger equations with artificially chosen wavefunctions (= usually containing many, many terms ) with a lot of freely-adjusted parameters take an enormous amount of time, and the quantum mechanics cannot obtain the total energy close to the experimental values, unless they use almost infinite numbers of basis functions or terms for the chosen trial wavefunctions.
It means it is impossible to obtain the exact total energy distinguishing very small van der Waals energy by using these very rough and time-consuming Schrödinger equation calculation methods where the choice and slight adjustment of parameters significantly, unstably and unreliably influence and change the calculated total energy.
To compute molecular energy, all the current physicists blindly and automatically try to use the quantum mechanical most popular approximation called density functional theory (= DFT ) or Kohn-Sham theory that outrageously replaces the whole molecule consisting of many electrons by only one pseudo-electron model ( this p.3-5 ).
↑ This most-widely-used quantum mechanical one-pseudo-electron DFT approximation always includes the serious self-interaction errors (= SIE ) or delocalization errors caused by the fictitious Coulomb repulsion inside the same single electron.
And the DFT must artificially choose fictitious exchange-correlation energy functionals to deceptively obtain the energies close to experimental values ( this p.43 ).
The problem is physicists can Not find the universally-exact DFT exchange-correlation functional, which means all calculated results by the present DFT's wrong illegitimate exchange-correlation functionals are invalid and fake ( this p.10-lower, this p.2-left-first-paragraph ).
No matter what exchange correlation energy functionals physicists artificially create, they always find the case where the calculated (total) energies disagree with the experimental values ( this p.17 ). ← No universally-exact DFT exchange-correlation functional exists.
Even in the most reliable hybrid exchange-correlation functional called B3LYP whose parameters are artificially fitted to experimental energy values of small atoms, the DFT calculated energy values disagree with experiments especially in medium ~ large-sized molecules and metals ( this p.8-right-upper ).
So even in the current quantum mechanical illegitimate methods of just artificially choosing fake electron's wavefunctions, pseudo-potentials and adjusting many free parameters, it is impossible to obtain the exact total energies of molecules, to say nothing of larger proteins ( this p.18-lower ).
Physicists gave up obtaining the exact (absolute) total energies, and instead, try to obtain the fictitious "relative energies" that may artificially cancel errors of initial and final products in the deceptive quantum mechanics and its most-widely-used DFT calculations ( this p.2-right ).
As shown here, it is intrinsically impossible to get the exact precise total energies in any quantum mechanical methods especially in estimating very weak van der Waals energies (=~ 0.01 eV, ← calculated energy errors even after adjusting exchange functional's parameters for reducing errors is larger than this, this p.2-3 ) playing important roles in biological reactions between molecules and proteins.
Even if they can know the (meaningless) total energies of initial and final molecular or proteins' states, they cannot predict whether the chemical or enzymatic reactions will happen or not.
Because chemical reactions usually need some activation energies or stochastic thermal fluctuation energies irrelevant to the total energies of molecules or proteins.
Chemical and enzymatic reactions such as bond breaking and forming happen only between some particular combinations of atoms, so we need to know only the basic tendency and properties of what atoms tend to cause some particular chemical reactions.
We do Not need to waste too much time in calculating the meaningless total energies including all inner and outer electrons just to know the chemical and biological reactions that happen only between the surfaces of some particular atoms and molecules.
But the unphysical quantum mechanics can Not stop wasting time in calculating the meaningless total energies of all atoms and molecules, because its unphysical Pauli repulsive or molecular bond exchange energies lacking physical forces cannot be expressed, unless they calculate the total energies.
Even in the current (pseudo-)classical molecular dynamics or molecular mechanics lacking real electrons, they recklessly try to obtain the meaningless total energies of all atoms by artificially adjusting many, many fictional spring-like bond and angle parameters, which must be changed in different molecules (= No transferability ), in vain.
↑ The current quantum mechanics and molecular dynamics only looking at (meaningless) total energies containing unphysical exchange energies lacking physical (exchange) force can Not tell us in which direction each atom or electron wll move, unlike the real objects whose moving direction can be easily predicted by looking at real forces applied on them.
As a result, all the current manistream molecular-computing methods such as quantum mechanics, DFT and molecular dynamics are unable to simulate the actual molecular and protein bahavior due to their reckless time-consuming attempt to obtain the meaningless total energies of all atoms and electrons (= often, causing errors and deviation ) just for estimating very weak intermolecular van der Waals force.
In spite of the current dead-end useless quantum mechanical model, physicists Never try to explore deeper true atomic mechanism to seek the better, simpler and more practical molecular simulating methods based on real movable electrons and real forces. ← Their unscientific attitude stopping 'asking' and stopping delving into deeper true mechanism stops our scientific progress forever.
As I said, when we construct practical buildings, cars, planes and machines, we do Not need to calculate the meaningless, time-consuming total energies of all atoms and electrons of the whole building or car, much less unphysical quantum mechanical exchange energies.
Also in designing and building some molecular nano-machines potentially useful for curing intractable diseases, we do Not need to waste too much time in calculating the meaningless total energies of all atoms and electrons. ← All we need to know is the shape, size and basic surface property of each atom and molecule.
Time-consuming calculations of all atomic and electrons' energies recklessly conducted by all the current quantum mechanical methods such as DFT and molecular dynamics (= MD ) are meaningless and a huge waste of time, because those quantum mechanical DFT and molecular dynamics cannot predict unknown molecular or proteins' behavior. ← After all, physicists have to compare their simulation model with experimental data to re-adjust their bond parameters, exchange-correlation functionals, basis sets, and check whether their simulation is right or not.
To move ahead to building really-useful nano-mahines from each atom, we must remove the current highly unrealistic and inconvenient mainstream quantum mechanical atomic model based on the contradictory exchange energy, and replace it by more practical and realistic atomic model that can express real forces and movable separable electrons among atoms.
(Fig.2) It's indispensable to treat each atom and molecule as ordinary components for building practical machines, but the unphysical quantum mechanical old rules and unreasonable restrictions forbid it !
As you know, all things and parts for constructing useful buildings, cars and machines are made of atoms and electrons.
It means we should be able to touch and manipulate each atom and molecule for building useful nano-machines which can potentially cure the current intractable diseases using the already-existing excellent technology such as atomic force and scanning tunnel microscopes (= of course, the more improvement, the better ).
But the current quantum mechanics forbids physicists from treating atoms and electrons as realistic separable objects, instead, it forces them to go down the rabbit hole of wasting an enormous amount of time just in dealing with meaningless time-consuming unphysical antisymmetric wavefunctions or fictitious exchange energy lacking real (exchange) forces.
If we want to treat each atom and electron as a real tangible object like a real component for building machines, first, we have to separate each atom, electron from other different atoms and electrons. ← Even this basic necessary procedure is impossible in quantum mechanical unphysical Pauli antisymmetric wavefunctions.
To move an object in some direction, we needs "forces". So we have to identify and express the sources of the actually-measurable real forces such as Coulomb electric forces and Pauli repulsion using real physical matter ( instead of unreal virtual particles ), which basic indispensable procedure is also impossible in the contradictory quantum mechanical model that obstinately refuses to admit the actually-measurable Pauli repulsion ( this p.2 ) to be a real force ( this p.6-top, this p.8-lower ).
Pauli repulsion is definitely one of real measurable forces which can be easily felt as contact or normal forces ( this p.5 ) when we touch some (rigid) objects (= though the ridiculous quantum mechanics claims two things can never touch each other to avoid admitting Pauli repulsion is a true force ).
In order to express this real Pauli repulsion as a real thing or force, we must prepare some force's source or carriers in addition to the electric charges, which is possible only if we admit the existence of some real substance or medium filling space as the source of this Pauli repulsion.
Because if there are only electric charges such as electrons and protons in the empty vacuum, this empty vacuum can only exert Coulomb electric force without Pauli repulsion where the sizes of the atoms and molecules would drastically decrease from the current observed ones.
But the old rules, restrictions and vested interests of the current academia and contradictory mainstream science stand in the way of these normal scientific developmental processes.
↑ Admitting real substance or medium filling space as Pauli repulsion's real source contradicts not only (fantasy) quantum mechanics but also (paradoxical) Einstein's relativity, which is also one of reasons the mainstream physicists obstinately avoid exploring deeper truth, and refuse to replace the current dead-end useless mainstream physics by new practical models, which unscientific attitude of the current academia has stopped our scientific advancement for curing diseases forever.
Einstein special and general relativity was proved to be definitely wrong due to their irreparable paradoxes in elecromagnetic force, time, mass and wave, which true paradoxes are intentionally ignored in ordinary textbooks and the media that often mention only seeming paradoxes that have easy solutions.
Many experiments have confirmed that the electron's de Broglie wave is a real thing actually affecting the electron's motion and trajectory through observing its interference where destructive interference of de Broglie wave is proved to have the power enough to exclude the electron from the destructive-interfering regions or frindges.
Like the ordinary sound and water wave's interference, this actually-observed interference or diffraction of electron's de Broglie wave and light definitely needs some real substance or medium filling the space to explain the two-slit interference experiments, if you don't want to rely on the unrealistic quantum mechanical parallel worlds.
And this actually-verified electron's de Broglie wave destructive interference can naturally explain the realistic Pauli repulsion's palpable source, force carriers between separable electrons without relying on the fictitious contradictory quantum exchange energies lacking exchange forces.
To avoid the destructive interference of this electron's de Broglie wave, only the limited number of electrons can enter each energy level, and the circumference of each orbit must be an integer times de Broglie wavelength which can give the definite size of each atom combined with nuclear charges or Coulomb electric force.
Coulomb electric force and electric charges were originally "empirically-determined forces" or things that could be known only from actual experiments and observing physical phenomena, using various techniques and instruments.
Like this Coulomb electric force, which was once an "empirically-determined force", first, we have to actually measure and investigate the detailed properties of the (realistic) Pauli repulsion or electron's de Broglie wave's destructive interference power (with respect to Coulomb attraction) using the atomic force microscopes or some more improved devices to determine each atomic concrete "shape" and size that reflect the scope of contact force or the electron's de Broglie wave's repulsive influence.
After investigating and knowing the basic property (= what particular bond breaking and forming are likely to happen ), size and shape of each atom and molecule, we should move ahead to putting together those known atoms and molecules to construct slightly bigger molecular devices, and then, measure and confirm those slightly bigger molecular device.
In this way following the normal technological procedure like building ordinary cars and machines by putting together parts, components whose properties are measured and confirmed one by one, we can gradually combine smaller molecular components whose properties can be measured and confirmed by microscopes in order to construct bigger practical molecular machines.
Of course, in order to construct practical buildings, cars, planes or machines, we do Not need to know the meaningless total energies of all atoms and electrons constituting the buldings, cars and planes. ← This is the important point.
↑ The unrealistic quantum mechanics bound by the contradictory Pauli exchange energy rule has No other choice but to try to obtain these unnecessary total energies of all electrons and atoms constituting any bigger molecules or proteins in vain (= often disagreeing with experimental results, this p.3-6 ) by artificially choosing pseudo-potentials and fake wavefunctions with many freely-adjustable parameters for unsolvable Schrodinger equations without knowing the real "forces" that are indispensable for moving atoms and building bigger devices.
The normal scientific developmental procedure for constructing buildings or (molecular) machines is strictly forbidden by the outrageous quantum mechanical old obsolete rules where physicists are blindly forced to use the unphysical quantum mechanical model or one-pseudo-electron DFT approximation with artificially-chosen exchange correlation functionals whose exact form is unknown, without being allowed to seek the real physical meaning or replace it by more practical and simpler atomic models, just to protect the old academic vested interests like Galileo era.
Due to the unphysical quantum mechanical Pauli antisymmetric wavefunction's rule, every electron must unrealistically spread over all different atoms, which quantum mechanical electron without shape is inconveniently inseparable from other electrons.
In the quantum mechanical most-widely-used one-pseudo-electron DFT model, the unphysical plane waves (= basis sets ) spreading all over (interstitial) space or multiple different atoms are often chosen as ones representing outer valence electrons ( this p.3-lower, this p.8-First-principle calculation, this p.7, this p.16-17 ).
All these quantum mechanical valence electrons expressed as fictitious spreading plane waves (= basis set ) are treated as one pseudo-electron DFT model ( this p.12-13, this p.19 ) by artificially creating (pseudo-)periodicity even in isolated molecules in DFT ( this p.21, this p.27-40, this p.9 7th-paragraph ).
And each nucleus and inner (core) electrons are often combined as one pseudo-potential waves called "pseudo-wavefunction ( this p.16, this p.3-left )" whose radius and strength are just artificially-adjustable parameters with No power to predict anything.
(Fig.3) Each atom should be treated as a real component for constructing bigger molecular devices. ← We don't need the useless fruitless quantum mechanical calculation of total and exchange energies at all
All tangible physical objects with definite sizes and shapes on the earth are movable separately by pushing and pulling them using forces such as "contact force" that is real Pauli repulsion.
And all these physical separable objects are made of atoms and electrons, so we should be able to treat each atom and electron as a real separate physical object with definite size and shape, and move them separately using real forces like components for buildings.
Like constructing cars, buildings and machines by moving and combining parts and components with known measurable sizes and shapes, if we can know the concrete shape and size of each atom and molecule, we can construct any useful nano-machines potentially curing diseases by moving and putting them together.
↑ We already have this technology of measuring and moving each single atom using atomic force microscopes, but we still cannot construct useful nano-machines, Why ?
↑ In this process (for constructing cars, buildings or molecular nano-machines ), we do Not need the useless meaningless quantum mechanical calculations of (fake) total energies E (= or Hamiltonian H ) of all atoms and electrons of the whole buildings at all ( this p.6 ).
↑ We can build practical cars or machines, even if we do Not calculate the meaningless time-consuming Schrödinger equations, total energies and unphysical exchange energies.
But in the old quantum mechanical procedure, it is impossible to know the true atomic wavefunctions or vague (probability) shapes, unless we can calculate Schrödinger equations and get these maningless total energies using artificially-chosen Pauli exchange antisymmetric wavefunctions.
The problem is that except for the simplest one-electron hydrogen atom whose energies agree with Bohr's realistic atomic model, quantum mechanics cannot solve any Schrödinger equations for multi-electron atoms and molecules.
↑ At this moment of unsolvable Schrödinger equations, it is intrinsically impossible for any quantum mechanical methods to know the true atomic shapes (= probability wavefunctions ) or total energies.
In spite of these unsolvable useless quantum mechanical equations, physicists try to artificially choose fake wavefunctions and pseudo-potential energies called exchange-correlation energy functionals with many freely-adjustable parameters to illegitimately obtain fake total energies in quantum mechanics and its most-widely-used one-pseudo-electron DFT approximation.
Quantum mechanical models must expand these artificially-chosen fake electron's wavefunctions using basic unit wavefunctions called basis sets (= artificial choice of basis sets is just "art", Not science ) which are often linear combinations of plane waves with freely-adjustable coefficient parameters c especially in calculating molecules and metals by one-pseudo-electron DFT ( this p.2-18, this p.7-DFT Calculations of hBN/Ir ).
And they have to construct the annoyingly complicated Pauli antisymmetric wavefunction or Slater determinants by combining these artificially-chosen basis functions or basis sets where each electron's (sub-)wavefunction must be orthogonal (or orthonormal ) to each other ( this p.15, this p.26 ), which unphysical quantum mechanical rules take physicists an enormous amount of time without giving real physical pictures or mechanism.
Each electron's wavefunction, basis set or plane wave allegedly expressing electrons has to always spread over all space without clear boundaries, which means quantum mechanical model cannot give the concrete shape and size to each atom and electron.
And the quantum mechanical unphysical Pauli exchange energy allegedly caused by (pseudo-)kinetic energy change lacks real (exchange) force or physical meaning ( this p.4-lower, this p.3 ).
So according to the quantum mechanical model, contrary to the actual fact, physicists are supposed to be unable to even push or pull each atom using real forces, instead, they are blindly forced to obtain fake total energies E (= because this is the only way of useless quantum mechanics guessing the electron's pseudo-behavior ) by integrating chosen antisymmetric wavefunctions with chosen exchange pseudo-potential energies in vain.
↑ This meaningless quantum mechanical procedure for trying to obtain (pseudo-)-total energies instead of directly giving the concrete shape or force to each atom (= calculating total energies of all atoms and electrons composing buildings or cars is an unnecessary step for constructing practical buildings or cars ) that physicists have blindly relied on for a long time without exploring the deeper real physical mechanism is the reason why our basic science has come to a deadend with No practical application.
(F.4)
See this.
(Fig.5) Even when two atoms hit each other, quantum mechanical fictitious electrons and nuclei cannot move realistically, which are different from two actual balls hitting !
Due to the useless unsolvable multi-electron Schrödinger equations, quantum mechanics had No choice but to rely on ad-hoc approximation treating multi-electron atoms or molecules as one pseudo-electron density functional (= Kohrn-Sham ) theory (= DFT, KS ) with artificially-chosen pseudo-potential.
↑ In this current mainstream quantum mechanical one-pseudo-electron DFT or quasiparticle model, it is impossible to give actual shapes to individual atoms or explain the motion of those individual atoms realistically.
The current only method of simulating or explaining dynamical motion of molecules is the extremely-time-consuming molecular dynamics (= MD ).
Ab-initio or first-principle molecular dynamics (= AIMD, FPMD ) such as Car-Parrinello molecular dynamics (= CPMD ) or Born-Oppenheimer MD (= BOMD ) is based on quantum mechanical unphysical one-pseudo-electron DFT approximation ( this p.7-lower~p.8, this p.26, this p.1-middle-last~p.1-right-upper ) with artificially-chosen pseudo-potential ( this 1st-paragraph ) without giving actual shapes to individual atoms.
In this ab-initio MD (= CPMD, BOMD ), physicists have to artificially choose (or guess ) the DFT's one-pseudo-electron density consisting of unphysical plane-wavefunction with (artificially-chosen) coefficients ( this p.14-22 ), and (fictional) pseudo-potentials ( this p.2, this p.10-right-10.1 ).
In each time step (= each time step Δt updating nuclear positions and electron's coefficients must be very short = less than 1 femtosecond or 1 × 10-15 s ) of BOMD, they have to find (adjust) the coefficients giving the lowest (ground-state) energy within the artificially-chosen pseudo-electron's wavefunctions or plane-wave basis sets (= ab-initio MD cannot move electrons realistically, this p.32-33 ), and move only nuclei classically, which takes unrealistically too much time.
Car-Parrinello molecular dynamics (= CPMD ) using fictitious electron mass (= μ, this p.2-left-(1), this p.39 ) and DFT pseudo-potential ( this p.28-32, this p.12 ) slightly modifies the coefficients (= c ) of the artificially-chosen plane-wavefunctions ( this p.12 ) in each time step, repeatedly to try to arrive at the lowest energy state in the end ( this p.16 ) = trying to find the coefficients giving the lowest-energy ground-state.
This paper ↓
p.35- Ab-initio molecular dynamics (= AIMD ) relies on (one-pseudo-electron) DFT model.
p.40- Ab-initio MD tries to move only a nucleus with mass M by (fictitious) classical Newtonian motion.
p.41- Ab-initio MD expresses electrons as nonphysical plane wave with artificially chosen basis sets, coefficients c, and pseudo-potential.
p.44- Ab-initio MD (= CPMD ) tries to change the coefficients c of the unphysically-spreading plane wave or pseudo-electron, instead of moving real electrons.
This p.2-left-(5)-middle says
"The ion (= nuclear ) dynamics
in Eqs. (5) may have a real physical meaning, whereas
the dynamics associated with the (electron's) ψ's and the α's
is fictitious and has to be considered only as a tool to
perform the dynamical simulated annealing (= electron's wavefunction's motion or its coefficients' change is fictitious in ab-initio molecular dynamics )."
This paper ↓
p.19-20 In Born-Oppenheimer molecular dynamics (= BOMD ), they restrict the wave function ψ to be the ground state adiabatic wave function (= fictitious electron's wavefunction's coefficients are adjusted to give the lowest ground state energy within the chosen wavefunction or basis set ) at each instant of time, and only nuclei are moved classically.
p.21-22 uses one-pseudo-electron DFT.
p.27-28 Car-Parrinello molecular dynamics tries to keep electron's wavefunction (= coefficients ) close to ground-state by using fictitious electron's mass.
This paper ↓
p.3-1.1.1 Limitations say
"This is generally true for insulators and semiconductors, but not for metals, for
which CPMD (= ab-initio Car-Parrinello molecular dynamics ) cannot be directly applied. In addition, a small enough fictitious
mass for the electrons must be chosen to allow the orbitals to follow the ions
adiabatically.
CPMD also suffers from the typical drawbacks that DFT suffers from, such as
the inability to describe van der Waals forces, the band gap problem and the
inability to accurately describe highly correlated electrons with localized d and
f orbitals."
p.4-6 Ab-initio MD or CPMD just changes coefficients (= c ) of the unphysical artificially-chosen pseudo-electron's wavefunction.
This paper ↓
p.16-(45) uses fictitious mass μ
p.36--2nd-paragraph says "one–electron equations involving an effective one–particle Hamiltonian of Kohn-Sham DFT"
p.41-lower & p.48-3.1.5 mention pseudo-potentials
This ab-initio molecular dynamics (= AIMD ) based on the unphysical mainstream quantum mechanical one-pseudo-electron DFT model is unreal, useless, far more time-consuming ( this p.12, this p.2, this p.1-abstract, this p.2-2nd-paragraph ) than the (pseudo-)classical MD based on empirical pseudo-potential or force field ( this p.2-left-1st-paragraph ).
Even in the latest researches, the (time-consuming) ab-initio molecular dynamics (= MD ) can simulate only impractically-short ps (= picoseond ) motion of molecules with a less than 1 fs time step ( this p.3-left-1st-paragraph ), which cannot simulate much longer important biological or chemical reactions (= seconds ~ hours ).
This p.7-right-ab-initio molecular dynamics simulations used (DFT) pseudo-potential to conduct only 10-20ps-motion simulation with 1.0fs time step.
This unphysical fictitious ab-inito molecular dynamics of CPMD is unreasonably used to express even the atoms actually observed by microscopes ( this p.10-calculations, this p.5-3. this p.8(or p.7)-DFT calculation ), which quantum mechanical unphysical model hampers nano-technology ( this introduction-4th-paragraph ).
(Fig.6) Quantum mechanical model is useless and ignored by biologists and chemists researching cells or proteins observed by atomic force microscopes.
One-pseudo-electron density functional theory (= DFT ) or Kohn-Sham model is the most-widely-used quantum mechanical approximation in physics and chemistry.
But in fact, all quantum mechanical models such as DFT can be used only for non-practical researches on very small molecules.
In researches on all other medium~large-sized molecules, proteins and cells, scientists are unable to utilize the impractical time-consuming quantum mechanical models such as DFT, hence, the practical use of quantum mechanics for biology, medicine or drug discovery is hopeless.
The quantum mechanical DFT approximation is often used in researching only one or several small molecules observed by atomic force microscopes.
↑ The point is DFT has to artificially choose different fictitious exchange-correlation energy functionals with many freely adjustable parameters such as pseudo-potential, empirical van der Waals-dispersion and DFT-U functionals ( this p.3-right ) in different situations ( this p.6-left-lower, this p.8-left-lower, this p.4-DFT-calculation ), because No universally-exact DFT functional has been found.
It is known that all DFT exchange-correlation functionals failed to give the exact total energies especially in larger molecules and metals ( this p.5-left-lower, this p.1-left ).
So physicists actually utilizing this DFT full of a lot of errors tend to avoid mentioning their incorrect total energies (in their research papers), which are useless, and instead, they focus only on "the relative energies or other values" where intrinsic DFT errors could be masked.
And physicists often try to explain the molecules observed by atomic force or scanning tunnel microscopes using unreal quasiparticle models ( this p.11-polaron-quasiparticle ), detached from reality.
In research on the medium-sized ~ large molecules such as graphene and COVID-19 protein, both quantum mechanics and its one-pseudo-electron DFT approximation take too much time and tend to give a lot of errors, so (pseudo-)classical molecular dynamics (= or MD ) with the empirically-obtained pseudo-potential energies called force field parameters are used ( this p.8-MD simulation, this p.11-molecular dynamics simulation, this p.8-molecular-dynamics simulation ).
But these (pseudo-)classical force fields of classlcial molecular dynamics cannot treat real electrons, so it cannot handle any chemical reactions involving bond breaking and formation ( this p.4-last, this p.5-left ).
And classical molecular dynamics (= MD ) has to prepare an enormous number of free-parameters such as bond lengths, bond angles and fictitious non-integer partial charges in each different molecules, which often fail ( this p.2-left-last~right-upper ) and cannot be used as the universally-exact parameters = Non-transferable, which means the force field bond parameters obtained from one molecule cannot be used in other molecules ( this p.2-1st-paragraph, this p.9-10, this p.1-right-last-paragraph ).
Furthermore, even this current alleged fastest molecular-simulation method = (pseudo-classical) molecular dynamics (= MD ) takes an unrealistically too much time for medium~large molecules (= ab-initio MD based on quantum mechanical DFT takes much, much more time than this pseudo-classical MD, so more impractical, this p.2-introduction-1st-paragraph ), hence, it is inapplicable to practical simulation of molecules or porteins observed by atomic force microscopes (= AFM ).
This introduction-11th-paragraph says
"In principle, it should be possible to compare experiment with
MD simulations. However, AFM (= atomic force microscope ) experiments usually take place on
microsecond to millisecond time scale, or even longer, which
is out of reach of standard unbiased MD (= molecular dynamics ) simulations."
In the current chemical and biological researches on observing larger molecules, proteins, nano-particles and cells by atomic force microscopes, No quantum mechanical methods such as DFT or No classical molecular dynamics are used, because all the current molecular-simulating methods, whether they are quantum or not, are inapplicable to practical science.
In practically-large molecules, proteins or nano-particles, researchers are unable to use the time-consuming (useless) quantum mechanics, DFT or pseudo-classical molecular dynamics (= MD ).
Instead, they have to give up considerting actual intermolecular interactions (= basic science stops progressing ), and rely on biological tools such PCR, cloning, immunoblotting.. using natural antibodies or enzymes obtained from natural bacteria, virus or animals which can Not be designed nor made from the (useless) quantum mechanical calculations, as shown in these articles making No mention of quantum mechanics, DFT or molecular dynamics ( this p.6-8, this p.2-4, this p.6, this p.6, this p.7-10, this p.11-12, this p.5-6, this p.3-6 ).
↑ It means all the current applied-science researches on biology, chemistry and medicine, which are unable to use any atomic-simulating methods such as quantum mechanics, molecular dynamics or other real atomic models, are unable to look into or utilize actual atomic or molecular interactions, hence, all these current applied science is useless and unusable for curing deadly diseases or drug discovery.
(Fig.S) Quantum mechanical DFT just artificially choosing (fictitious) spin parameters cannot predict ferromagnet or antiferromagnet. → No evidence of spin
Ferromagnet or antiferromagnet is said to be caused by (fictitious) electron spin according to quantum mechanics.
But an electron is known to be Not actually spinning.
Furthermore, quantum mechanics just choosing free spin parameter J has No ability to predict ferromagnet or antiferromagnet.
Quantum mechanical Schrodinger equations are unsolvable and unable to predict any multi-electron atoms or molecules.
Quantum mechanics has to rely on the rough approximation called density functional theory (= DFT ) that tries to treat the whole material as one-pseudo-electron or quasiparticle model with artificially-chosen pseudo-potential (= different exchange-correlation functionals give different spin interaction parameter J as shown in this p.7-Table.III ).
In this mainstream DFT, physicists have to choose various freely-adjustable parameters such as fictitious wavefunctions, pseudo-potential (= U, J, this p.6-right-1st-paragraph ), (spin) magnetic moment (= m, this p.4~p.7, this p.136(p.128)-2nd~3rd-paragraphs ), and numbers of electrons (= n ) in different spin states ( this p.16-1st-paragraph ). ← No quantum mechanical prediction
This p.11-3rd-paragraph says
"In practice treated as fitting parameters, i.e., adjusted to reach agreement with
experiment: equilibrium volume, magnetic moment, band gap"
↑ Instead of (useless) quantum mechanical prediction, these artificially-chosen magnetic moment parameter (= m ), electron spin number (= n or spin polarization parameter ζ ) determine whether the material is ferromagnet or antiferromagnet ( this p.53(p.45),p.60-63, this p.8-p.12. p.21(or p.20) ).
DFT pseudo-potential parameters (= U, J ) must be chosen from experimental results in most cases (= instead of being predicted by quantum mechanics, this p.4-right-3rd-last-paragraph, this p.2-left-2nd-last-paragraph, this p.3-1, this p.3, this p.22 chose t or J, this p.6-right-1st-paragraph ).
This p.5-right says
"However, apart from the intentionally fitted
LSDA+U result, all functionals overestimate the antiferromagnetic coupling J by at least a factor of two, and perform
even worse for the interchain coupling J ( this p.16, this p.8-left-1st-paragraph )"
So quantum mechanics (= unphysical spin model ) relying on various freely-chosen parameters ( this p.10, this p.21 ) cannot predict whether the material is ferromagnetic or antiferromagnetic ( this p.22(or p.21)-2nd-paragraph ), which means there is No evidence that (anti-)ferromagnetism is caused by electron spin.
Stable ferromagnet is caused by the realistic electron's orbits (= instead of spin ) meshed with each other by Coulomb electric interaction.
See this.
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