Questions tagged [gamess]
Questions related to the GAMESS(US) or GAMESS(UK) software.
21
questions
3
votes
1
answer
80
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. ...
- 806
4
votes
0
answers
67
views
Convert reduced density matrix in A.O. basis from GAMESS to pyscf
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
208
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
281
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.
...
- 1,709
12
votes
0
answers
176
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
307
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
187
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 ...
- 399
8
votes
1
answer
133
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
150
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
207
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
225
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
241
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
243
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, ...
- 6,216
5
votes
1
answer
172
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 ...
- 1,202
17
votes
3
answers
575
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 ...
- 6,216
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, ...
- 6,216
9
votes
1
answer
245
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 ...
- 6,216
11
votes
1
answer
194
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 ...
- 3,868
15
votes
2
answers
260
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 ...
- 6,216
13
votes
2
answers
513
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:
...
- 2,333
17
votes
1
answer
593
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. “...
- 3,868