Multiwfn forum

solan

Member

Registered: 2024-04-02

Posts: 7

R lenght

Hello good:
First of all, congratulations on your program, it is extremely useful and easy to use.
My question is about rotatory strength R, which can appear in calculations as R length or R velocity. I have read that R velocity is origin-independent, but I don't understand what this term means. You can help me?

In most of the calculations I have performed the values of R length and R velocity are quite similiar or nearly identical, but I have found a case where there is a transition (the first one) with a very different value for both magnitudes. Have you any idea about this phenomena?

Thanks in advance

sobereva

Tian Lu (Multiwfn developer)

From: Beijing

Registered: 2017-09-11

Posts: 1,768

Website

Re: R lenght

Hello,

If basis set is complete (finitely large basis set), R length and R velocity will be the exactly the same. However, since R length converges with respect to basis set size more rapidly than R velocity, therefore R length is more recommended to use in practice. If you use a larger basis set, perhaps the difference will be notably smaller.

"origin-independent" denotes that the result keeps exactly unchanged when you translating the system, which is equivalent to displacement of origin.

solan

Member

Registered: 2024-04-02

Posts: 7

Re: R lenght

Thank you very much for your response