Skip to main content

Questions tagged [mrcc]

For questions about (or involving) the MRCC electronic structure software package.

Filter by
Sorted by
Tagged with
6 votes
1 answer

Using the same input (MINP) file, why does MRCC fail with a "normal" fort.55 file, but succeeds with a longer fort.55 file that has duplicate entries?

I have the following fort.55 file: ...
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 ...
2 votes
1 answer

MRCC/CFOUR interface bug for a single atom calculation?

I am trying to run the calculation of the DBOC using CFOUR/MRCC interface for a single atom. The calculation runs with no issues without MRCC (i.e. if CC_PROG=MRCC is removed from the ZMAT file below),...
5 votes
0 answers

Core-valence separation (CVS) keyword in MRCC program [closed]

I am interested in using the CVS option in CI calculations to get core-excited states. I tried to use the MRCC program which possesses this option according to the manual (cvs=...). I performed some ...
8 votes
1 answer

Interfacing MRCC with CFOUR for dynamic polarizability

I have asked this question on the MRCC forum but did not get an answer. I am trying to understand how to use CFOUR with the MRCC program for computing dynamic polarizability. To begin with, I am ...
5 votes
1 answer

ssr functional for the dft=userd in MRCC package

I found the nice userd example with the standard functional in the latest MRCC manual but I wonder if one can also use ssr (...
4 votes
1 answer

Crash of DF-CCSD or DF-CCSD(T) geometry optimization (MRCC package)

I am interested in geometry optimization at the CCSD(T) or DF-CCSD(T) level, with MRCC. The calculation, however, crashes when executing prop: ...
4 votes
1 answer

Which programs can calculate corrections to the Born-Oppenheimer approximation?

I need to calculate the electric dipole moment of molecules like HD, in which the electric dipole moment is zero in the Born-Oppenheimer approximation (meaning that it's absolutely necessary to ...
17 votes
3 answers

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 ...
10 votes
2 answers

What are Pair Natural Orbitals?

Recently, I came across electron correlation methods that use local pair natural orbitals (LPNOs) or domain-based local pair natural orbitals (DLPNO), such as DLPNO-MP2, DLPNO-CCSD etc. The dynamic ...
11 votes
2 answers

Analytic gradient for DLPNO-CCSD

Is there a formula for analytical gradients (for geometry optimization) for the DLPNO-CCSD method? I ask because I know that it is not implemented in ORCA. Maybe PNO-CCSD is implemented in MRCC or ...
16 votes
3 answers

How to calculate homolytic bond dissociation energies?

An experimental colleague asked me how hard it would be to calculate homolytic bond-dissociation energies for different phosphonates which are involved in a Hydrophosphination. The compounds include ...