Unanswered Questions

97 questions with no upvoted or accepted answers
16
votes
0answers
158 views

How to set up a local server for iQmol on macOS?

I'm trying to set up iQmol as a tool to submit calculations to Q-Chem on our lab machines to make access to it easier for OChem students. Unfortunately, it is not working properly "from the box&...
15
votes
0answers
104 views

Derivatives with respect to user defined vibrational modes

I'm doing some property calculations that depend on a sum of derivatives of some quantity with respect to normal vibrational modes. I was hoping to find some physical intuition relating the type of ...
15
votes
0answers
79 views

How to find the projected Hamiltonian for lowest flat-band in general?

In [1], starting with the bosonic Hamiltonian (Eqn. 1) for the dice lattice model with half flux density (with Ahronov-Bohm phases incorporated), \begin{equation} H=-t\sum_{\langle j,\mu\rangle}(a^\...
14
votes
0answers
47 views

Benchmark Timings of Machine Learning Potentials vs Molecular Mechanics Force Fields

Machine learning is an increasingly common tool for developing force fields for molecular dynamics simulations. It's not totally clear what should be considered a machine-learning potential, but let's ...
13
votes
0answers
114 views

Promising functionals for transition metal chemistry

I'm looking to get your opinions on the most promising density functionals to use for thermochemistry and kinetics of transition metal complexes. However, as eloquently laid out by Tom Manz on this ...
13
votes
0answers
78 views

What are the advantages of different point defects calculation tools?

As far as I know, there are mainly PyCDT, PyDEF, pylada and some part of pymatgen. As a new user to those tools, which one would be a good choice? pycdt: Python Charge Defects Toolkit (PyCDT) is a ...
12
votes
0answers
192 views

How to understand dynamical spin structure factor?

A newish area of interactions between quantum Monte Carlo (QMC) and experiments is in spin spectra. Recent improvements in stochastic analytic continuation have made it much easier to compare/extract ...
11
votes
0answers
89 views

First order variation of the wave function

The first order variation of the wave function $\Delta \psi_n$ is obtained by standard perturbation theory(Eq. 25 of ref 1): \begin{equation} (H_{SCF}-\epsilon_n)|\Delta \psi_n \rangle = -(\Delta V_{...
11
votes
0answers
72 views

What does it mean to assign group operations to distinct sets for space groups?

I am trying to understand space groups in crystallography. In International tables for crystallography, for a nonsymmorphic space group, they list some symmetry operations. 8 of them are listed under ...
11
votes
0answers
59 views

Bioisosteric replacement using SMARTS (KNIME and RDKit)

I am trying to create a KNIME workflow that would accept a list of compounds and carry out bioisosteric replacements (we will use the following example here: carboxylic acid to tetrazole) ...
11
votes
0answers
104 views

Is there a software that has implemented forces of TDDFT calculations for solids?

I'd like to investigate the structural relaxations of the excited state for periodic systems. BSE and TDDFT are two promising methods for this purpose. While there is a discussion on BSE Is there a ...
11
votes
0answers
85 views

Empirically determining thermostat damping factor

tl;dr Is there a way to determine an appropriate thermostat damping factor given a timestep size and a numerical integration method? I am computing a set of simulations in LAMMPS, using ReaxFF, ...
10
votes
0answers
55 views

Deciding the number of CPUs for a DFT calculation

If I am using Quantum ESPRESSO for my work, how can I know the number of CPUs necessary for a certain DFT calculation?
10
votes
0answers
57 views

What are the methods of modeling Jahn-Teller effects in a solid-state material?

The Jahn-Teller effect arises from the symmetry breaking (distortion) of the local environment for the crystal field of 3d transitional metal ions.The distortion result in energy saving of electronic ...
10
votes
0answers
99 views

Why does the Wolff algorithm slow down in a 4-body Ising model?

In the paper that introduced "Self-learning MC" (an ML-inspired MC technique, as I understand) the authors consider a many-body Ising model as an example to show the efficiency of their ...

15 30 50 per page
1
2 3 4 5
7