Following my previous question Here, I had been trying to implement One and Two electron integrals in the code. I am currently stuck at the implementation of the OS Scheme, where I read the references [1] and [2] to look for the implementation. I understood the recursion parts where the electron is transferred from one center to another using the following recursion relations: $$ \theta^N_{i+1,j,k,l,m,n}=\theta^N_{i,j+1,k,l,m,n}-X_{AB}\theta^N_{i,j,k,l,m,n}$$ $$ \theta^N_{i,j,k+1,l,m,n}=\theta^N_{i,j,k,l+1,m,n}-Y_{AB}\theta^N_{i,j,k,l,m,n}$$ $$ \theta^N_{i,j,k,l,m+1,n}=\theta^N_{i,j,k,l,m,n+1}-Z_{AB}\theta^N_{i,j,k,l,m,n}$$ $$ \theta^N_{0,0,0,0,0,0} = F_N(pR^2_{PC})$$ where A and B are centers of the the basis functions and ordered set (i,k,m) and (j,l,n) are the angular momentum terms in x,y and z direction, and N is the order of Boys function. My question concerns the calculation of total integral from this scheme.
References:
- Helgaker, _Modern Electronic Structure Theory
- Obara. S, and Saikia. A, Efficient recursive computation of molecular integrals over Cartesian J. Chem. Phys. 84, 3963 (1986) Gaussian functions
