Cartesian vs spherical gaussian WFN representation

[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.