quack/src/IntPak/NormCoeff.f90

30 lines
655 B
Fortran

function NormCoeff(alpha,a)
implicit none
! Input variables
double precision,intent(in) :: alpha
integer,intent(in) :: a(3)
! local variable
double precision :: pi,dfa(3),dfac
integer :: atot
! Output variable
double precision NormCoeff
pi = 4d0*atan(1d0)
atot = a(1) + a(2) + a(3)
dfa(1) = dfac(2*a(1))/(2d0**a(1)*dfac(a(1)))
dfa(2) = dfac(2*a(2))/(2d0**a(2)*dfac(a(2)))
dfa(3) = dfac(2*a(3))/(2d0**a(3)*dfac(a(3)))
NormCoeff = (2d0*alpha/pi)**(3d0/2d0)*(4d0*alpha)**atot
NormCoeff = NormCoeff/(dfa(1)*dfa(2)*dfa(3))
NormCoeff = sqrt(NormCoeff)
end function NormCoeff