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13 votes
Accepted

Analytic gradient for DLPNO-CCSD

Note that the DLPNO method is only implemented in ORCA. There are indeed analogous and similarly efficient and accurate methods, the PNO-LCCSD method in Molpro [doi.org/10.1021/acs.jctc.7b00799] and ...
Peter Nagy's user avatar
12 votes

What significant matter modelling methods are implemented in commercial software, for which there is no freeware alternative?

I think the way this question is asked is a little too simplistic. In order to execute a computational project, there is always more than one calculation required. Even if you are happy with the ...
annakrylov's user avatar
11 votes
Accepted

How to calculate homolytic bond dissociation energies?

Multi-reference or single-reference? While it is appreciated that near dissociation there will be a near-degeneracy of orbitals, requiring a multi-reference treatment, fortunately we don't have to ...
Nike Dattani - No Free Time's user avatar
11 votes
Accepted

Can MOLPRO (2012) calculate SA-CASSCF gradients with cc-pVDZ?

The MOLPRO 2012.1 manual is no longer online, although there is an archive of at least some of the pages and you can try your luck for finding the pages you want on the archive, but it might not be ...
Nike Dattani - No Free Time's user avatar
11 votes
Accepted

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

Basis set name versus number of total orbitals I would like to first address a part of the question that appears to be a misconception about the use of a 6-31+G(d,p) basis set, since you wrote: "...
Nike Dattani - No Free Time's user avatar
10 votes
Accepted

How to interpret molden AO/MO coefficients?

Okay, so there are many layers to this question. cc-pVTZ for H is [5s2p1d/3s], which comes out to 3 + 2*3 + 5 = 3+6+5 = 14 basis functions per atom, which are composed of 16 primitives (the contracted ...
Susi Lehtola's user avatar
  • 19.7k
8 votes

Analytic gradient for DLPNO-CCSD

As far as I know, analytic gradients for DLPNO-CCSD are not available in ORCA. Analytic first derivatives are available for both closed-shell and high-spin open-shell cases, which could be used for ...
Dipayan Datta's user avatar
8 votes

What significant matter modelling methods are implemented in commercial software, for which there is no freeware alternative?

One can also pose the opposite question, which may be more interesting: what significant matter modelling methods are implemented in open source software, for which there is no commercial alternative? ...
Susi Lehtola's user avatar
  • 19.7k
8 votes

How to calculate homolytic bond dissociation energies?

BDEs are calculated by the below procedure: Calculate initial energy Perform homolytic bond cleavage and separate fragments Calculate energies of the fragments, add the energies together Calculate ...
kskinnerx16's user avatar
  • 1,546
7 votes

Understanding the difference between Dunning and Karlsruhe basis sets

The definition of fast and slow is a bit complicated. I just tried an organic molecule with about 100 atoms and ran two jobs: One with def2-TZVP (1647 AO basis sets, 1872 CAOs) and one with cc-pVTZ (...
Uwe's user avatar
  • 196
7 votes

Understanding the difference between Dunning and Karlsruhe basis sets

What systems are you running? Turbomole is designed for basis sets employing segmented contractions (like the Karlsruhe sets are), whereas the Dunning sets are generally contracted. While any code ...
Susi Lehtola's user avatar
  • 19.7k
7 votes

Choosing an active space for CASSCF using Molpro

As a developer of MOKIT, I would like to recommend the automatic CASSCF computation using the automr utility in MOKIT. We do not need to manually choose/permute ...
jxzou's user avatar
  • 806
6 votes
Accepted

What do the parameters at the top of an FCIDUMP file mean?

MS2 is related to the spin. Specifically, it is the number of unpaired electrons. Your molecule is a singlet, which is why it says ...
Nike Dattani - No Free Time's user avatar
6 votes

Choosing an active space for CASSCF using Molpro

First of all, your syntax isn't exactly the way the MOLPRO manual for the CASSCF program (called "Multi") instructs: OCC,n1,n2,…,n8; CLOSED,n1,n2,…,n8 ...
Nike Dattani - No Free Time's user avatar
6 votes

How to calculate homolytic bond dissociation energies?

One thing the other answers haven't mentioned is the zero point and thermal corrections to the BDE. As mentioned in the Wikipedia Morse potential article, a geometry optimization will take you, by ...
Geoff Hutchison's user avatar
6 votes

Interface between PySCF and Molpro

Interoperability between quantum chemistry packages is almost non-existent when it comes to more complicated data structures, and there is no real standard for wavefunction or density matrix ...
TiborGY's user avatar
  • 395
5 votes

How are one-/two- particle reduced density matrices printed in mainstream programs?

1RDMs are just simple matrices, which can be stored in either dense or sparse form, possibly combined with triangular storage (the matrix is often symmetric). 1RDMs are passed around in a number of ...
Susi Lehtola's user avatar
  • 19.7k
5 votes

MOLPRO: is there an analogue of the Gaussian FCHK file?

Following the HORTON information webpage about supported data file formats from section 2.4.3. Wavefunction formats (using a Gaussian basis set): ...
Camps's user avatar
  • 23.4k
4 votes
Accepted

How to determine occupied and closed orbitals for a Molpro CASSCF calculation?

The occupied orbital pattern of 13 7 6 2 that you got from your Hartree-Fock calculation is not unique. For example, I've just run an RHF calculation on PdO with ...
Nike Dattani - No Free Time's user avatar
4 votes

Correlation tables between irreps for f orbitals

The simplest way to check the correlation between $f$-type basis functions in a high-symmetry point group (say $D_{\infty h}$) and in its Abelian subgroup (say $D_{2h}$) or any other subgroup is to ...
Raghunathan Ramakrishnan's user avatar
3 votes
Accepted

In Molpro, how to calculate the orbital angular momentum?

"However they are listed with parity -1, and: "Expectation values are only nonzero for symmetric operators (parity=1)"." This matches the ...
Nike Dattani - No Free Time's user avatar
3 votes

In Molpro, how do I get the two-electron operator for angular momentum from a CI calculation?

In the first sentence of this Introduction to MOLPRO, MOLPRO is described as a "system of programs", not just one program. The first link you provided is for the program called ...
Nike Dattani - No Free Time's user avatar
3 votes

How does MOLPRO choose active orbitals in a CASSCF calculation?

You fixed the occupation within symmetries by the command "occ,6,3,3,2" and asked the program to make CASSCF for the lowest 5 singlet states of symmetry 1 ...
TKorona's user avatar
  • 39
3 votes
Accepted

Interface between PySCF and Molpro

So what I originally wanted is possible, with a little python scripting. To achieve this, a fcidump file containing h1 and h2 needs to be created by moplro. This entails running an SCF in molpro ...
Jannis Erhard's user avatar
1 vote

Excited states of Lithium in MOLPRO

The author of the question found a solution: "Hi Andrea and Tyberius, sorry for the late reply, my problem is already solved, thank you!" If anyone (including the author of the question) ...

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