Ab-initio molecular dynamics (= AIMD ) is too time-consuming, useless, dealing with unreal atoms.

Home page
Molecular dynamics is useless

Ab-initio (or Car-Parrinello ) molecular dynamics (= AIMD, CPMD ) treating multiple electrons as one pseudo-electron DFT with pseudopotential is useless, unable to predict anything.

(Fig.1) Ab-initio MD just changes coefficients (= c ) of artificially-chosen fake electron's wavefunction lacking real atomic shape.

Ab-initio molecular dynamics (= MD ) is useless, unable to predict anything, more time-consuming than ordinary impractical MD.

Due to unphysical quantum mechanical wavefunction lacking real atomic shape, today's only molecular simulating method called ( classical ) molecular dynamics (= MD ) is impractical, too time-consuming to calculate each atomic position at short-time intervals many, many times, based on artificially-chosen force field potential.

Ab-initio or first-principle molecular dynamics (= AIMD, FPMD, CPMD ) changing fictitious electron's wavefunction based on DFT pseudo-potential is much more impractical and more time-consuming than the impractical classical MD ( this-p.2-left-1st-paragraph,  this-p.2-I-introduction,  thisp.19-3rd-paragraph ).

In Ab-initio MD, quantum mechanics has to treat the whole atoms as one pseudo-electron DFT (= Kohn-Sham ) model through artificially-chosen exchange pseudo-potential (= functional ) that is fake ab-initio (= empirical ), unable to predict any physical values ( this-p.2-2nd-paragraph,  this-p.2-left-last-paragraph~p.2-right,  this-p.23-lower ).

Ab-initio MD takes too much time in DFT calculating coefficients of artificially-chosen fictitious electron wavefunctions.

In this impractical ab-initio MD, only nuclei (= positive ions ) are treated like classical particles, moved gradually by differentiating the total fake energy E with respect to each nuclear coordinate R_I (= force = space derivative of total potential energy, this-p.6 ) at short-time intervals.

In Born-Oppenheimer (ab-initio) molecular dynamics (= BOMD ), they have to artificially choose fake one-pseudo-electron DFT wavefunction ( this-p.14-(40) ), and update their coefficients (= c ) by the extremely time-consuming self-consistent field (= SCF ) method at short-time intervals ( this-p.23,p.27,p.32 ). which is completely impractical ( this-p.35,  this-p.2 ).

Ab-initio Car-Parrinello MD relies on fictitious electron's mass, which is also too time-consuming, impractical.

So ab-initio MD often uses the slightly simpler Car-Parrinello molecular dynamics (= CPMD ) using fictitious electron's mass μ ( this-p.36,  this-p.9,  this-p.7,22 )

↑ In this CPMD, they update each coefficient (= c ) of the artificially-chosen pseudo-electron's wavefunction (= φ = basis set ) by differentiating the total energy E with respect to the coefficient c ( this-p.41,p.44,  this-p.12-(6.10),  this-p.5,p.7 ) at extremely short-time intervals (= 0.1 fs, this-p.12-22,  this-p.3,p.12 ) together with updating nuclear positions.

So ab-initio molecular dynamics just changes fictitious electron (fake) wavefunction's coefficients instead of moving real electrons.

And this ab-initio MD (= CPMD, BOMD.., old Ehrenfest MD is not used now, this-13-upper ) needing calculations of both nuclear and fictitious electron's states at much shorter time intervals (= 0.1fs ) is more impractical and more time-consuming than classical MD updating only atoms at the intervals of 2fs ( this-p.19-lower,  this-p.2 ).

The 4th-last and last paragraphs of this hyped news (7/8/2025) say
"Throughout this research, ..the team have investigated the vibrational properties of titanium nitride using Raman spectroscopy, a non-destructive chemical analysis technique which provides detailed information about chemical structure."

"The ultimate goal of this project is to gain an atomistic-level understanding of the role played by the atoms"  ← This means the atomistic-level understanding still has Not been achieved.

↑ Raman spectroscopy's resolution (= just measuring light reemitted from the material ) is about 1μm ( this-middle-Raman is used for microscopic,  this-resolution ), which can Not distinguish single atoms of less than 1nm, nor clarify the atomic mechanism.

↑ This research paper ↓

p.1-abstract says "but a fundamental understanding of how their structures evolve during electrocatalysis remains unknown"  ← quantum mechanics failed to clarify the material's atomic mechanism.

p.4-left-computational methods used the impractical ab-initio molecular dynamics based on unreal DFT's pseudo-potential, which can Not clarify real atomic mechanism.

Quantum mechanical mainstream density functional theory (= DFT ) treats the whole material as one pseudo-electron model with artificially-chosen spin pseudo-potential parameters.  ← No quantum mechanical prediction, so No evidence of spin

(Fig.S)  Quantum mechanical DFT just artificially choosing (fictitious) spin parameters cannot predict ferromagnet or antiferromagnet.  → No evidence of spin

Electron spin is unreal, irrelevant to (anti-)ferromagnet.

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 ).

Quantum mechanics just choosing free parameters cannot predict ferromagnet or antiferromagnet.

In this mainstream DFT, physicists have to choose various freely-adjustable parameters such as fictitious wavefunctions, exchange-correlation-pseudo-potential (= U, J,  this p.6-right-1st-paragraph,  this-p.1-right-last ), (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's exchange-potential and 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.

Quantum mechanics or DFT relying on artificially-chosen exchange pseudo-potentials can Not predict electron spin or magnetic moments of materials

This research paper ↓

p.30(or p.29)-3rd-paragraph says "The treatment described electrons in a non-interacting, fictitious potential"

p.47(or p.46) says " The most straightforward inclusion of magnetic materials in DFT is to attach two spinors ( χ+ and χ−) to the wave function (= artificially-chosen fake wavefunctions for expressing unreal spin )"

p.95(or p.94)-Table 4.7 exchange (spin) interaction parameters J are different among different chosen exchange-correlation (= XC ) potential functionals such as LDA, PBE, rSCAN.. ( this-p.6,  this-3rd-paragraph ),  ← Spin exchange parameters affected by the artificial choice of exchange potential means the spin magnetic moments are Not quantum mechanical prediction.

p.96(or p.95)-3rd-paragraph says "DFT is known to overestimate the magnitude of the exchange interaction parameter"

p.126(or p.125)-2nd-paragraph says "the magnetism within iron arsenide depends heavily on the choice of XC (= exchange-correlation ) functional"

Stable ferromagnet is caused by the realistic electron's orbits (= instead of spin ) meshed with each other by Coulomb electric interaction.

The 2nd, 5th, 10th, 2nd-last paragraphs of this hyped news (7/24/2025) say
"Understanding the origins of magnetism—deeply rooted in quantum mechanics—enables scientists and engineers to manipulate magnetic properties for further innovative applications and emerging technologies."  ← hype

"With their method, the team successfully mapped out every electronic contribution to magnetic interactions, tracing the intricate exchange pathways through both magnetic atoms"  ← This quantum exchange interaction lacking real exchange force is unreal, which abstract unphysical math ( this-p.9-upper ) clarifies No real magnetic mechanism.

"This breakthrough therefore provides a solid foundation for the rational design and precise engineering of magnetic materials, accelerating the path toward smart, efficient, and tunable technologies"  ← hype

Quantum mechanics just choosing free parameters and artificial models can Not predict nor clarify any real magnetic mechanism of materials.

↑ This research paper ↓

p.1-abstract says nothing about technological application, contrary to the above hyped news.

p.1-inroduction-2nd-paragraph says
"While these consequences of magnetic exchange are well understood, the exact quantitative determination of magnetic exchange between a pair of atoms for a specific material remains challenging"  ← Quantum mechanics fail to clarify material's magnetism nor (unphysical spin) exchange interaction.

p.4-p.6 shows this research with No experiment just artificially chose this unphysical exchange interaction parameters J without quantum mechanical prediction nor clarifying any real mechanism.

This-p.11-left-2nd-paragraph says
"allows us to extract the magnetic exchange interaction,... The method is however tied to the choice of DFT basis (= one fictitious electron model clarifying No real mechanism ), implementation of exchange correlation functional used in DFT and to specific computational parameters (i.e. k-points sampling, Hubbard U corrections within DFT+U, etc.)."

↑ So the present quantum mechanics relying on artificial choice of various free parameters and exchange energy functional of one-pseudo-electron DFT model can Not predict nor clarify any fictional spin exchange interaction, so No technological development, contrary to hypes.

Feel free to link to this site.