Wave function analysis at DLPNO-CCSD(T)

dummy@example.com (saeed_E) — Tue, 16 Jun 2026 04:52:52 +0000

Dear Tian,
In the Multiwfn manual, I found:
"Here I illustrate how to make Multiwfn able to analyze (relaxed) CCSD(T) wavefunction
produced by ORCA. The version of ORCA I currently use is 6.1. Below is an example input file
named H2CO.inp, which calculates H2CO at CCSD(T)/cc-pVTZ level using AUTOCI module.
! autoci-CCSD(T) cc-pVTZ verytightSCF"

Is it also possible to use autoci-DLPNO-CCSD(T)? Please suppose we performed a SP calculation on the DFT-optimized geometry (G16) using DLPNO-CCSD(T)-TightPNO to obtain a highly accurate energy and also a "T1 diagnostic" to ensure whether the system is really single-reference. It seems, in addition to T1 diagnostic", the orbital OCC must also be checked. Thus, the above procedure given in Multiwfn should be performed but, the SP is at DLPNO-CCSD(T)-TightPNO, not CCSD(T).

In advance, many thanks for your kind attention.
Sincerely,
Saeed

Multiwfn forum / Wave function analysis at DLPNO-CCSD(T)

Wave function analysis at DLPNO-CCSD(T)