Questions tagged [nwchem]

For questions about the NWChem computational chemistry program.

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9 votes
2 answers

Quantifying relativistic effects in DFT calculations

I am wondering what is the best approach to quantify the contribution of relativistic corrections to a result of an electronic structure calculation. As far as I understand, from a user perspective ...
Szgoger's user avatar
  • 624
1 vote
0 answers

Is there a correct way for compiling and installing NWChem software with all modules from a source code on Linux Mint?

I have been trying to compile and install NWChem v6.8 from a source code on Linux Mint 21.2. According to instructions received from chatGPT, the following steps have to be done: Install necessary ...
SFriendly's user avatar
  • 897
4 votes
0 answers

Does NWChem support RI approximations in the MP2 part of double hybrids? [closed]

I abandoned the use of M11-L and instead turned to B2PLYP for my molecule in my previous question, as M11-L seemed in fact to be very poor for my application. Since B2PLYP contains MP2, I looked up ...
Kanghun Kim's user avatar
4 votes
1 answer

How to properly compute volume bound by surface with uniform electronic density, from data in a cube file?

As a example, I ran the following DFT single point energy calculation on NWChem, to get a cube file with electron density data for 1.1.1-Propellane (the geometry was optimized beforehand): ...
ksousa's user avatar
  • 4,108
4 votes
0 answers

How to perform a DFT/def2-PPCBS extrapolation on NWChem [closed]

I'm planning to analyse an extremely complex molecule on NWChem(it's practically the only free computational package available package here, and the molecule is so large that running a seemingly ...
Kanghun Kim's user avatar
10 votes
1 answer

Understanding emission spectra using TDDFT calculation

I did a TDDFT calculation to get the emission spectra of my molecule. Here are the first five roots for the emission calculation: ...
Bikash Patra's user avatar
4 votes
2 answers

Energy per unit cell in NWChem differs for different supercells despite the same k-points density

I try to compute the unit cell energy of the $\ce{Ti2CO2}$ MXene with NWchem. Computing the 1x1 supercell with 4x4x1 K-points grid I got -1875 Ha. Computing the 2x2 supercell with 2x2x1 K-points grid ...
user36313's user avatar
  • 730
10 votes
1 answer

Understanding absorption spectra using TDDFT calculation in NWCHEM

I did a TDDFT calculation using B3LYP functional and ground state optimized structure in NWCHEM. The TDDFT portion of the output is the following: ...
Bikash Patra's user avatar
11 votes
1 answer

Calculating hyperpolarizability in NWChem

I'm trying to make a pipeline geometry optimization -> calculation of polarizability/hyperpolarizability. And NWChem seems pretty good for it, the only thing I can't understand its how to calculate ...
Roman's user avatar
  • 2,373
23 votes
3 answers

What is the largest system that has been studied by the coupled cluster method?

This is parallel to the analogous question about the largest DFT calculation: What is the largest material that has been studied using density functional theory? I assume we allow high performance ...
Paulie Bao's user avatar
  • 3,953