g Function

public elemental function g(i, j, k, l) result(res)

The two-electron integral in chemist’s notation

Convention in the purple book[@purple_book] or the Shavitt paper[@Hinze1981] and many more. $g_{I, A, J, B} = < I J | 1 / r | A B >$

The function exists to have a direct translation of the pen and paper equations into code.

Arguments

Type	Intent	Optional	Attributes		Name
integer,	intent(in)			::	i	Spatial orbital indices
integer,	intent(in)			::	j	Spatial orbital indices
integer,	intent(in)			::	k	Spatial orbital indices
integer,	intent(in)			::	l	Spatial orbital indices

Return Value real(kind=dp)