Multiwfn forum

anupthms000

Member

Registered: 2020-05-23

Posts: 3

Calculate ∆r and Λ indices to characterize various electron excitation

Dear Sr
I am trying to calculate ∆r and Λ indices to characterize various electron excitation of Donor-Acceptor-Donor type dyes. The ∆r values obtained is less than 1 A. Can I be definite that my molecule is having LE type excitation than charge transfer type. Or these data is only valid for Donor- Acceptor dyes or is it valid of symmetric D-A-D type dyes.

sobereva

Tian Lu (Multiwfn developer)

From: Beijing

Registered: 2017-09-11

Posts: 1,773

Website

Re: Calculate ∆r and Λ indices to characterize various electron excitation

Using ∆r to judge type of excitation for D-A-D type of system may be misleading. If the CT character is strong but the CT direction is symmetric with respect to A, the ∆r may still be very small.

I highly encourage you to use hole-electron analysis module (see Section 4.18.1 of Multiwfn manual for example) to visualize distribution of hole and electron, only when the CT is found to be unidirectional, the ∆r can be used to discuss CT character.