Cartesian vs spherical gaussian WFN representation

General discussion of the Cambridge quantum Monte Carlo code CASINO; how to install and setup; how to use it; what it does; applications.
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Vladimir_Konjkov
Posts: 185
Joined: Wed Apr 15, 2015 3:14 pm

Cartesian vs spherical gaussian WFN representation

Post by Vladimir_Konjkov »

Hello CASINO developers.

I wonder why the CASINO uses a spherical representation for the gaussian basic functions, while the сartesian representation requires a smaller number of computations to find both the values, derivatives and Laplacian etc.
There is no difference only for S and P the orbitals.
A spherical representation would be logical if the random walk of electrons was specified in spherical coordinates around single center, but this is not so.

Сould you tell me the reason for using the spherical representation, thank you in advance, Vladimir.
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