The poster was presented at the Psi-k 2022 conference, August 22-25.

We present the recent progress in developing a high-performance and user-friendly program suite – the Cornell-Holland Ab-initio Materials Package (CHAMP) -- for performing accurate and efficient quantum Monte Carlo (QMC) calculations of molecular systems. A prominent capability of CHAMP is the efficient computation of analytical interatomic forces, also in combination with the fast evaluation of multi-determinant expansions and their derivatives. The code utilizes the latest processor instructions to perform vectorized tasks and is optimized for upcoming exascale computing facilities.

The code offers various capabilities such as variational Monte Carlo (VMC), diffusion Monte Carlo (DMC), and optimization of many-body wave functions by energy minimization for ground and excited states. The other prominent features of CHAMP include the efficient computation of analytical interatomic forces and a compact formulation for the fast evaluation of multi-determinant expansions and their derivatives.