Perform the ground state probability ampltiude (GSPA) technique on an arbitrary molecular system. This first part of this code takes in a set of walkers and their descendant weights and calculates the pseudo normal coordinates by diagonalizing the mass-weighted matrix of second moments of internal coordinates.
The second part of this code calculates the transition energies and intensities associated with these normal modes by performing the GSPA approximation (outlined in This Paper). Currently very much under construction! Being pulled out of GroundStateApproximation.