Questions tagged [gaussian]

For questions related to the Gaussian electronic structure program

Filter by
Sorted by
Tagged with
11
votes
1answer
60 views

Why does Gaussian ignore the opt=maxcycles keyword for optimizations?

I have been using both Gaussian09 and Gaussian16 recently to optimize some metal complexes. The Gaussian manual (for both versions) indicates that the maximum number of steps in a geometry ...
11
votes
1answer
123 views

What units are used in Gaussian 16 for dipole derivatives output?

I ran a frequency analysis employing Gaussian 16 on MP2/6-31+G(d,p) level of theory with the keyword iop(7/33=1) in order to have access to dipole derivatives with ...
8
votes
1answer
60 views

Calculation of dispersion energies for organometallic complexes with Gaussian

I've tried to calculate dispersion energies of some organometallic complexes with the Gaussian software using WB97XD/Gen (...
9
votes
1answer
201 views

How to calculate the band structure of a protein molecule

I want to calculate the band structure of a protein molecule. How can I do it using Siesta of Gaussian? I am thinking about QE/VASP as the number of atoms are 600 and computationally it is not ...
8
votes
1answer
173 views

Problem obtaining a Raman spectra of a graphene structure

I am trying to obtain the Raman spectra of a graphene structure using Gaussian. I used the input below, but when I did it, I got this error: ...
7
votes
1answer
36 views

What does “Test job not archived” mean?

I am running frequency computation with geom=connectivity in Gaussian. It all converges now but at the very end of the last convergence it says: ...
6
votes
1answer
66 views

Gaussian: Transition state convergence question

I am running a TS computation in Gaussian 16. It performs several steps. At the end of each there is a summary on whether Maximum Force, ...
10
votes
1answer
122 views

How to generate accurate displacements along normal modes?

How can i displace my structure along a particular normal mode, without coupling to other modes ? Rather than a exact mathematical procedure, I am more interested in a software/script/package that can ...
10
votes
3answers
158 views

CCSD and CISD size-consistency problem

I have performed a Gaussian16 calculation to explore the size-consistency problem for the CISD method. The system I am studying is the water dimer and the results are not what I expected at first. I ...
7
votes
1answer
57 views

PES of Tetramethylthiuramdisulfid / Problem with Disulfidbridge

I like to perform a DFT Study on Tetramethylthiuramdisulfid. So I made a structure optimization for my start structur with PW6B95D3/aug-cc-pvtz to get a good structure to begin my dihedral scan to get ...
30
votes
5answers
2k views

What is a good replacement for Gaussian?

When I started studying computational chemistry (circa 2007), my supervisor used to tell me about the controversy surrounding Gaussian, Inc. regarding the banning of researchers involved in the ...
8
votes
0answers
65 views

Using “soft” constraints / bias in geometry optimization?

I study molecules weakly bound to nanoclusters and surfaces. During geometry optimization, I often run into problems like for example a small metal cluster behave nicely and has a given, stable ...
6
votes
0answers
56 views

Two-stage unbinding & binding energies with DFT

I'm trying to calculate the stability of the product of a coordinate bonding process of molecules A and B in the polarizable continuum solvent model (PCM, solvent set to water). I'm getting energies ...
4
votes
0answers
50 views

How can I calculate and plot the Molecular orbitals (MO's) from the Gaussian wavefunction file?

This a follow-up question to my previous question. And as per the answer one could create M.O orbitals from the primitives. As a new user of Gaussian, is there any method (or algorithm) to followed so ...
7
votes
1answer
69 views

How do I interpret the Gaussian16 wavefunction file?

I'm new to gaussian16. The wave function file that I obtain as a result of the "Energy" calculation. It consists of five distinct parts : PART 1 : ...
10
votes
1answer
176 views

A concern about IRC results

I've run an IRC (intrinsic reaction coordinates) calculation from my TS (transition state) and got two minima for each side. I am concerned about them. One of them took about 100 steps to be achieved ...
10
votes
2answers
267 views

How to perform charge analysis for a molecule

I am doing dehydrogenation of a molecule (say $\ce{C12H12}$) and I want to do charge analysis for dehydrogenated system ($\ce{C6H6}$). How I can proceed? I can use Quantum ESPRESSO and Gaussian ...
10
votes
1answer
68 views

Calculate Redox Potential

I am interested in calculating some redox potentials of organic compounds (H,C,N,O,F,Cl,Br) in organic solvents such as MeCN. I do not need absolute agreement with experiments since this is just a ...
8
votes
1answer
44 views

Simulation of electronic potential from nanoparticles interacting with molecules

I work with SERS, where the Raman signal gets enhanced by the electric field of the nanoparticles. Now I like to simulate this kind of spectrum with Gaussian. I found a paper[1], where it looks very ...
9
votes
1answer
119 views

A good software for DFT optimization and nonlinear optical properties

I'm running a series of calculation for nonlinear chromophores. The general pipeline is geometry optimization (B3LYP/def2-TZVP) -> Frequencies -> Hyperpolarizability calculation (M06-2X (or CAM-...
9
votes
3answers
792 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, ...
8
votes
0answers
154 views

How to interpret second order perturbation theory analysis from NBO calculations? [closed]

The question is quite simple — how to interpret NBO results of second order perturbation theory analysis? As I have read several papers the most important interactions are $\pi\rightarrow\pi^{*}$, $LP\...
8
votes
1answer
1k views

How to fix Error Link9999 in Gaussian

I have a problem with geometry optimization in Gaussian software with M062X method. The structure was smoothly optimized using M062X/Gen. Nevertheless, I need very accurate results so afterwards the ...
7
votes
1answer
360 views

Is it possible to do TD-DFT/6-31G+(d,p) calculations on a laptop?

In the recent publication: "Density Functional Theory Calculation on the Structural, Electronic, and Optical Properties of Fluorene-Based Azo Compounds", the author claimed to have used ...
10
votes
3answers
564 views

Codes for post-processing Gaussian cube files?

I have generated MOs of a molecular system and I need to recreate its electronic density via $\rho(r)=\sum_{A_i}|\psi_i(\mathbf{r})|^2$ where $A$ is a set of occupied MOs. I am trying to do this via ...
8
votes
1answer
124 views

Is this G16 molecular hyperpolarizability error reproducible in other software?

I was trying to calculate the hyperpolarizability $\beta$ of a cluster of two water molecules in Gaussian16 using the route card: ...
6
votes
1answer
158 views

I get an error 'Conversion from Z-matrix to cartesian coordinates failed' in Gaussian09. Any suggestions?

I'm doing my calculations using G09W. My OS is Windows 7 (64-bit). This error occurs in the frequency calculation. What's even weirder is that it seems to happen right after everything is already ...
6
votes
1answer
265 views

I get this error in Gaussian09 even though I have enough memory. “Error termination in NtrErr: NtrErr called from FIOCnC.” Any suggestions?

Whenever read-write files get to about 20Gb, I get this error. I know that, in G09, one rw file is limited to 16Gb. So I have set the software to write several RWFs. But it still keeps producing this ...
12
votes
1answer
119 views

Calculate spin-spin coupling based on previous GIAO calculation with Gaussian

I used GAUSSIAN/GAUSSVIEW to calculate the GIAO Magnetic shielding tensor (ppm), but I forgot to calculate the Nuclear spin-spin coupling J (Hz). How can I use the .chk file or .log file to calculate ...
13
votes
2answers
171 views

A CCSD(T) geometry optimization in Gaussian09 is deviating too far from the minimum. How do I deal with it?

I am doing a CCSD(T) geometry optimization on a series of molecules. One of the geometry optimizations took about 2 weeks even though an analogous molecule with the same number of basis functions took ...
16
votes
1answer
368 views

How to map the electrostatic potential from GAUSSIAN, on a solvent accessible surface?

Gaussian cubegen and surface generators in Gaussview seem to only allow to map the ESP on SCF densities. I used G16 for the ESP generation. I would like to plot it on the solvent accessible surface. ...
12
votes
1answer
188 views

What is Gaussian16's read-file logic when using ONIOM with genecp?

I want to use the ONIOM keyword, like oniom(ccsd(t)/avtz:m06/genEcp) or similar, in conjunction with genecp. I want to use ...
13
votes
1answer
77 views

What is the precise location of the grid points/voxels in a Gaussian .cube file?

Assume that we have a cube file that contains Ni * Nj * Nk points, and an origin at 0, 0, 0, where are the data points actually ...
15
votes
1answer
303 views

CCSD(T) Transition State and Ground State Calculations in Gaussian09: “Unable to Determine Lambda”?

I’m doing CCSD(T) calculations (for both transition and ground state geometries) on a series of small molecules in Gaussian09. Several similar calculations terminated without any problems but one TS ...
17
votes
1answer
93 views

Discrepancy between numerical and transformed derivatives

This is related to a prior question of mine Derivatives with respect to user defined vibrational modes. While that one focuses on potential software to use for derivatives with respect to normal modes,...
12
votes
1answer
438 views

How to calculate sigma-profile using COSMO/RS and Gaussian 16?

Gaussian 16 claims to have an external tool to calculate sigma-profile COSMO/RS (Klamt) [1]. In the support website, there is a SCRF flag for COSMORS [2]. How do I calculate sigma-profile using ...
14
votes
2answers
238 views

What are the parameters that need to be calculated to design the structure of a molecule?

Before performing Molecular Dynamics on a co-polymer that doesn't have a ready-to-use structure anywhere, the monomer fragment was built in Avogadro software with 0 net charge, B3LYP theory and 6-31G(...
15
votes
1answer
148 views

What are good basis sets and functionals for Ni, Cd and Pb?

I will setup a single point energy calculation using Gaussian for a system containing atoms of B-N-Ni, B-N-Pb and B-N-Cd. The system are slabs of boron-nitride [1,2] interacting with those metals. ...
18
votes
1answer
131 views

Retrieving Translational and Rotational Modes

I'm doing some post-processing using the vibrational modes of a molecule to solve a linear system of equations, but I believe I need all the modes in order to have a single, well-determined solution. ...
11
votes
1answer
68 views

What is the meaning of periodic boundary condition for molecular systems?

Reading some Gaussian related documents (inputs, manuals, books), I found the possibility to setup periodic boundary conditions (PBC) in Gaussian. As Gaussian is developed only for molecular systems ...