Most active questions
35 questions from the last 30 days
10
votes
1
answer
204
views
How to specify isotopes in PySCF?
I'm using Qiskit-Nature with PySCF driver to calculate PES of simple molecules. And my question is about PySCF.
If there is a way to specify isotopes of atoms in PySCF, how may I do it?
PS: I've ...
- 103
5
votes
1
answer
572
views
After optimizing all of my structures, I discovered that one of them needs tighter convergence criteria. Is it mandatory for all to be re-done?
I'm working on optimizing a transition state for proton transfer and C-N bond cleavage.
I successfully obtained a transition state with a negative frequency corresponding to the expected process. ...
- 111
5
votes
2
answers
220
views
How to Keep Spin Vectors Fixed in Non-Collinear Antiferromagnetic SIESTA Calculations？
When using SIESTA to perform structural relaxation on non-collinear antiferromagnetic systems, I would like to incorporate magnetic effects while ensuring that the spin directions of certain atoms ...
- 61
5
votes
1
answer
107
views
What is the method to examine atomic bonds and hydrogen interactions after an optimization calculation?
I am currently working on a project to construct an energy profile for a reaction, which involves many optimization calculations. As a result, I need to verify numerous structures and ensure the ...
- 111
9
votes
1
answer
91
views
Recent Advances in Density Functional Theory (Mathematical Side)
I have been learning DFT with resources such as Engel and Dreizler's book, and it seems that higher level mathematics such as functional analysis appear frequently, especially in the more foundational ...
- 403
7
votes
1
answer
63
views
How to find the symmetry unique atoms of a molecule with a specified point group by any software or tool?
Suppose, for cyclopropane, the highest point group is D3h. However, I want to define it to its subgroup C2v for my NwChem calculation. But for specifying a different point group NwChem requires the ...
- 71
3
votes
1
answer
91
views
How do I input k-path in the bands.in file?
I use seek k-path website to find the suggested k-path and its coordinates for band structure calculation. Following is the input file (bands.in)
...
- 193
3
votes
1
answer
134
views
Different results from two different integral routines
I've been working on a Hartree-Fock code called Planck, where I've implemented overlap and kinetic integrals using three different methods: THO, OS, and Hermite, following Chapter 9 of Molecular ...
- 4,144
4
votes
1
answer
60
views
Why double hybrid functionals produce different results in different packages?
I'm calculating the single-point energy of the Nitrogen dimer using a double-hybrid functional called "mPW2PLYP". This is a widely known double hybrid functional available for use in ...
- 181
5
votes
1
answer
49
views
How do I find the updated cell parameters?
After performing relax-vc calculations for any system, I would like to find the cell parameters celldm(1), celldm(2), celldm(3), etc. using my output file. But I don't understand which of the values ...
- 193
1
vote
1
answer
43
views
Elec: transfer matrix has 0 elements. The self-energy cannot be calculated. Please check your electrode electronic structure
Here I added my electrode and scattering zone files. I would like to ask if there is any problem with the settings here. Z is the transport direction, xy is the periodic direction, and here I set the ...
- 11
3
votes
1
answer
53
views
Understanding the [13s8p/6s3p] contraction scheme for Mg⁺ and its reduction to [12s7p/5s2p]
Pacchioni et al. [1] used a [13s8p/6s3p] basis set for Mg⁺ in early cluster model calculations. The context is embedding, here is the list of primitives for the basis as given in the appendix:
...
- 145
3
votes
0
answers
61
views
Using libmsym for symmetrizing Molecular Orbitals
I have written a Hartree-Fock code (mostly as a learning exercise, and to use it as a tool in my lessons) that utilizes the libmsym library (following the advice here) to identify the symmetry of ...
- 4,144
4
votes
0
answers
39
views
Fourier transform expression of the coulomb interaction between the sheets(graphene)
Do you know any expression which can present the Fourier form of coulomb interaction between two graphene sheets separated by vacuum (as the figure above)?
Here S(w) is the transmission equation. ...
- 41
2
votes
0
answers
50
views
NEB convegence problem with LUA engine in siesta
I am having problems to converge NEB calculations with LUA engine within SIESTA. The NEB forces remain high after many days of calculations. Many of my NEB calculations so far never converge. I tried ...
- 123