# Questions tagged [mathematical-modeling]

Questions related to mathematical modeling of materials systems.

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### How to find magnetic materials in terms of magnetic point group?

Are there any methods to find materials in terms of the assigned magnetic point group? For example, I know the magnetic point groups $6'mm'$ and $6'22'$, and I want to find the corresponding ...
207 views

### What does it mean when the first order correction energy is 0?

Suppose I have the following Hamiltonian to start $$H_0 = \begin{pmatrix} 0 & 0 & 0 & 0\\ 0 & 0 & 2 & 0\\ 0 & 2 & 0 & 0\\ 0 & 0 & 0 & 0 \end{pmatrix}$$...
112 views

### What are the precise forms for the SU(2) and rotation matrices in VASP?

Some time ago, I conducted a discussion with Dr. Gui-Bin Liu on topological materials here. One relevant thing he said was: "The format of trace.txt file is only a necessary condition to be used ...
100 views

### Understanding derivation of discretized FIRE algorithm

Introduction/Preamble @SusiLehtola's answer to Basics of numerical energy minimization techniques used in molecular dynamics? mentions conjugate gradients, BFGS for energy minimization, Metropolis ...
54 views

### Basics of configuration initialization strategies used in molecular dynamics? [duplicate]

This answer to Basics of numerical energy minimization techniques used in molecular dynamics? mentions conjugate gradients, BFGS for energy minimization and Metropolis Monte Carlo (and the) the ...
193 views

### Basics of numerical energy minimization techniques used in molecular dynamics?

The question below describes my plan to make a basic molecular dynamics calculation using a Python script rather than a canned, self-contained program. There seems to be three parts: a model of the ...
84 views

### How to get a Wannier function for a tight-binding model numerically?

I have a question about construction of a Wannier function for a tight-binding model. Let's say we consider the tight-binding model of a 1D chain with two atoms (site A and B in a unit cell). In k-...
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### Do we know for sure that all atomic and molecular wavefunctions decay exponentially as r goes to infinity?

Slater type orbitals (STO) are considered to be more accurate than gaussian type orbitals (GTO) for atomic and molecular QM calculations because - among other reasons - they decay with $e^{-\alpha r}$ ...
114 views

### Can superconductivity be faked by using precise mathematics in a simulated circuit & specific materials in an actual circuit? [closed]

A type of electrical amplifier is proposed in which only magnetism and it’s analogous current exists for the most part. There is no voltage and no wattage (to speak of) in which electricity has to ...
182 views

### How to rotate polarizability tensor depending upon the molecular coordinates?

My question is somewhat related to molecular rotation. I have calculated the polarizability tensor of $\ce{HCHO}$ molecule in PSI4. The output tensor is this, ...
37 views

### Which specific perturbation do we consider applying to the potential when defining the energy derivative of the log derivative?

Norm-conserving pseudopotentials are defined such that the energy derivative of the log derivative of the real and pseudo wavefunctions agree at $r>r_c$. I understand that although valence ...
199 views