Questions tagged [coupled-cluster]
For questions related to the Coupled Cluster electronic structure method.
Extended Hybrid Methods
Hybrid DFT methods, where the functional is supplemented with Hartree-Fock exchange, have become increasingly popular due to their low cost and decent accuracy. Double hybrids, which mix in an MP2 ...
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 ...
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 ...
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 ...
What do size-extensivity and size-consistency mean?
I have heard both terms in various lectures and books on quantum chemistry, however, I have not found a proper explanation of them. As I understand now, size consistency of a method means for example, ...