Unanswered Questions
51 questions with no upvoted or accepted answers
22
votes
0
answers
248
views
Is there a software that can do 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 ...
- 15.9k
9
votes
0
answers
120
views
How does the line search in geometry optimisations work?
I am trying to write a Newton-Raphson geometry optimisation script in python (Current version of my code) using the energy, gradient and Hessian from Gaussian 16. In order to reach a minimum, I would ...
- 15.9k
6
votes
0
answers
105
views
What are the parameters in PySCF's Selected Configuration Interaction code
Dear StackExchange Members,
I'm using the native PySCF implementation of selected configuration interaction (SCI). However, I can't seem to find any documentation detailing the algorithm or various ...
- 20.1k
6
votes
0
answers
77
views
Benchmarking DFT vs Experimental Gaps - Confusion over Fundamental and Optical Gaps
Recently, I've come across discussions about the differences between fundamental (or electronic) bandgaps and optical bandgaps, with the two quantities differing mainly by the electron-hole binding ...
- 1,366
5
votes
0
answers
124
views
Geometry optimization with background charges in Gaussian with charge keyword
Gaussian requires the opt=z-matrix option when performing geometry optimization with the charge keyword. As can be seen in the following section from Gaussian's website:
To perform geometry ...
- 61
4
votes
0
answers
42
views
QUICK energy calculations in Amber Tools, vs Gaussian 16, vs Open Babel MMFF94
I am just getting back into molecular modeling, and looking for an open-source tool for generating some conformers from various SMILES to use in binding simulations.
Way back when I used Gaussian for ...
- 49
4
votes
1
answer
142
views
How to use rigid scan with dummy atoms in gaussian?
I am trying to use rigid scan using gaussian 09. In my case, there are three water molecules and I have placed a dummy atom at the centroid of the three water molecules. For simplicity, I want to ...
CommunityBot
- 1
4
votes
0
answers
59
views
May I change the ICntrl variable in Gaussian 16?
Ive been trying to do energy calculations under the influence of a perturbative field with the BLYP and B3LYP functionals. Using the following input files:
BLYP:
...
- 1,115
4
votes
0
answers
28
views
bandstructure calculation of two-dimensional ferrovalley (RuClBr) in quantum espresso
We try to calculate bandstructure of single layer RuClBr reported in fig.4 of 'https://pubs.rsc.org/en/content/articlelanding/2016/pq/d3nr00346a/unauth'. But our obtained bandstructure is not similar ...
4
votes
0
answers
121
views
Can I run Gaussian on Google Collab
Can I use Google Collab to run my Gaussian calculations? Due to the lower specification of my system, I can not run my calculations. I have to generate .wfn file. Is there any other idea or ...
- 20.1k
4
votes
0
answers
66
views
Struggling with Mixed Basis Set Inclusion for IRC Calculations
I'm trying to compute the IRC for a W complex, and I'm using Def2TZVP for W and 6-311G** for the rest of the atoms. However, when I include the mixed basis set, Gaussian 16 generates a syntax error.
I ...
- 7,171
4
votes
0
answers
94
views
How to compute only part of molecular Hessian accurately (hybrid Hessian or partial Hessian calculation)?
Hessian is required for minimisation and transition state (TS) optimisation algorithms. While the full Hessian at a certain level of theory is calculated usually for TS optimisation, usually ...
- 7,171
4
votes
0
answers
85
views
How to calculate charge transfer (CT) in NBO Analysis using Gaussian 09?
I have a coronene structure, functionalized with hydroxyl groups.
I want to calculate the charge transfer (CT) between the coronene and the hydroxyl group, using NBO analysis as implemented in ...
3
votes
0
answers
36
views
How to correctly set the high-symmetry point path block when there are breakpoints in the recommended path?
I watched Dr. Mohan's tutorial video, and the settings he provided are as follows:
...
- 31
3
votes
0
answers
40
views
How to calculate the second order hyperpolarizability gamma using Gaussian16?
Dear StackExchange community,
I'm trying to calculate the second order hyperpolarizability gamma γ (for example mthane) in guassian16 using solvent introduced manuallly .
here is my input
...
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