Multiwfn forum

smaity

Member

Registered: 2025-07-11

Posts: 1

Transition Dipole Moment from TrESP Charges

Dear Tian,

Thank you very much for developing and maintaining such a great program. Multiwfn’s ability to work with many different quantum chemistry packages is really impressive.

I noticed something unusual when using TrESP charges from quantum chemistry software like Gaussian or ORCA, followed by transition density analysis in Multiwfn. The transition dipole calculated by projecting the charges onto atomic positions seems to point in a different direction compared to the transition dipole moment vector reported by the quantum chemistry software.

I understand the direction of the transition dipole can be arbitrary due to phase conventions, but since both results are based on the same wavefunction, I expected consistency. It seems there may be a sign mismatch in how Multiwfn interprets the transition density compared to the original quantum chemistry software.

Thanks.

Best regards,
Sayan