Questions tagged [gamess]
Questions related to the GAMESS(US) or GAMESS(UK) software.
22
questions
2
votes
1
answer
47
views
Is it possible to plot the pDOS or visualize the molecular orbitals from GAMESS outputs?
I'm using the GAMESS software and want to try to plot the pDOS for my systems and visualize the molecular orbitals. I was thinking I could get the data from one of the ...
- 53
3
votes
1
answer
83
views
Error when trying to compile (after everything else has been done) GAMESS on Windows/WSL
I requested a copy of GAMESS, downloaded it, installed ATLAS because the config file said "please download a math library" and built ATLAS. I then tried to compile it using the compall file. ...
- 870
4
votes
0
answers
123
views
Convert reduced density matrix in A.O. basis from GAMESS to pyscf [closed]
I want pyscf to read the single-particle reduced density matrix computed by GAMESS.
However, I am having trouble because the matrix sizes in GAMESS and pyscf are different.
For example, the AO-...
- 41
7
votes
1
answer
283
views
How to freeze molecular orbitals in GAMESS-US?
I want to freeze some of the orbitals (e.g 1s orbital for all of the atoms in my molecule) in GAMESS-US, to save computation time. I guess I need to use $MOFRZ but I'm not sure how to. So far, I've ...
- 121
9
votes
3
answers
364
views
The number of orbitals in Gaussian/GAMESS log file
After calculating the energy of a $\ce{CH4}$ molecule with a 6-31G(d,p) basis set, I obtained the Gaussian/GAMESS log file and describe a part of the log file as follows.
...
- 1,779
12
votes
0
answers
204
views
How may I calculate the "effective transfer integral" in free electronic-structure software? [closed]
I would like to calculate the following four quantities in a free electronic structure program:
\begin{alignat}{2}\tag{1}
e_1&=\langle\phi_1|H^{KS}|\phi_1\rangle,\\
e_2&=\langle\phi_2|H^{KS}|\...
- 221
6
votes
2
answers
489
views
SCF not converging during RHF/STO-3G geometry optimisation
I'm new in the field of QM methods and I've run into a problem for which I can't find a solution online.
I have tried with different basis sets, I've raised the maximum number of iterations and number ...
user115080
7
votes
1
answer
246
views
Computing analytic derivatives of molecular Hamiltonians obtained from solving Hartree-Fock equations
I'm currently working on a quantum chemistry project, I am dealing with a second-quantized electronic Hamiltonian (corresponding to some molecule), written in terms of fermionic creation and ...
- 409
8
votes
1
answer
157
views
Excited states using ORMAS flag in GAMESS
I am trying to calculate the excited states using single reference CISD on $\ce{CH3OH},$ using ORMAS' CI-X option in GAMESS. As a test example I am using the $\ce{CH3OH}$ that has 2 core, 7 occ. ...
5
votes
0
answers
172
views
Calculating excited states using GAMESS CISD module [closed]
I am trying to compare the energies of the excited states of $\ce{C12H9N}$ molecule using the CIS and CISD module implemented in the quantum chemistry package in GAMESS.
While I can easily obtain the ...
6
votes
2
answers
223
views
Excited state normal mode frequency doesn't match for NH3
I am trying to optimize the geometry of excited state NH3 and get the corresponding normal modes for excited states. I am trying to get the frequencies as mentioned in this reference. They claim to ...
- 345
8
votes
1
answer
288
views
Optimization and vibrational analysis of excited state CO using GAMESS
I am facing some problems in performing HESSIAN analysis on excited states of molecules: I am testing it out with CO. My input file to GAMESS is pasted below. Could ...
- 345
9
votes
1
answer
273
views
Mismatched number of normal modes calculation in GAMESS
I am trying to calculate normal modes frequency matrix using HESSIAN calculation in GAMESS. Since we know that number of normal modes for a non-linear molecule is 3N-5 where N is the number of atoms. ...
- 345
9
votes
1
answer
286
views
How are molecular orbitals constructed from the coefficients and basis set?
When an SCF calculation is done in a QM program, the MO coefficients of the solution are printed into the output. Now, graphical softwares can plot 3D molecular orbitals from these coefficients, ...
- 6,601
5
votes
1
answer
229
views
GAMESS(US) Hessian calculation sometimes does not produce the IR intensities
I have noticed that for certain Hessian calculations that I run with GAMESS(US), the IR intensities are not produced in the log file. Below I have an example input card (without the molecule $DATA ...
- 1,222
17
votes
3
answers
792
views
How is "basis set projection" done?
I recently came across something called the basis set projection in Q-chem's manual. What it seems to do is to take the converged SCF in a smaller basis set, and then "projects" that onto a ...
- 6,601
9
votes
3
answers
1k
views
Which software is good with generally contracted basis sets?
Recently, I learnt that basis sets can be contracted as segmented (like def2 or 6-31G) or general (like cc-PVTZ, or ANO). The general contraction allows all the primitives to appear in all shells, ...
- 6,601
9
votes
1
answer
316
views
Energy decomposition analysis (EDA) at transition state
I am trying to understand the interaction between the nucleophile and the substrate for some SN2 reactions (e.g. $\ce{I- +CH3Cl->CH3I + Cl-}$) at the transition states. Now, it seems that EDA would ...
- 6,601
11
votes
1
answer
238
views
What are the trade-offs setting DIRSCF to either .TRUE. or .FALSE. (the default) in GAMESS (US)?
The first software I used to run calculations was Gaussian09. When submitting a input, I used to see a pattern of resource usage where the allocated CPU quickly maxed out, remaining high most of the ...
- 4,048
15
votes
2
answers
451
views
What is the difference between orbital localisation and NBO?
I am new to computational chemistry, I have used mainly GAMESS and Orca. In GAMESS, there are orbital localisation schemes like Pipek-Mezey, Ruedenberg-Edminston, etc. which generate orbitals that ...
- 6,601
13
votes
2
answers
703
views
How to get potential energy surface from GAMESS?
I'm trying to learn GAMESS and performing a simple PES scan of oxygen molecule. After the completion of the calculations I get a .log file with lots of sections like that:
...
- 2,363
17
votes
1
answer
749
views
Alternatives to VEDA 4 vibrational energy distribution analysis software?
Said software is useful when you need to assign the peaks in vibrational spectra to different vibrational modes found in a hessian calculation for a given molecule, as described in Jamróz, Michał H. “...
- 4,048