theochem/ModelHamiltonian

Two body integral

RichRick1 opened this issue · 3 comments

RichRick1 commented
  1. We need a function that convert a one and two body integral into anti-symmetrize for two body integral
    @gabrielasd has this function
    @PaulWAyers can help with math
PaulWAyers commented

Specifically need to have utilities for:
chemistry <-> physics notation
<-> antisymmetrized integrals (to support Triqs; see https://triqs.github.io/triqs/latest/documentation/manual/triqs/operators/util/hamiltonians.html?highlight=hamiltonian#module-triqs.operators.util.hamiltonians_)
<-> symmetrized (done)

PaulWAyers commented

Update: @gabrielasd and I worked through this yesterday, and I think we have a reasonable grasp of how to link to Triqs and what we need to do math-wise.

PaulWAyers commented

Good (great) reference on chemists' vs. physicists' notation.
http://vergil.chemistry.gatech.edu/notes/permsymm/permsymm.html

FCIDump and PySCF seem to use chemists' notation.

TL;DR:
In physics notation, the integrand is like <K*(1)L*(2)N(2)M(1)>. For chemists it is like <K*(1)M(1)L*(2)N(2)>.