Research
Current research in the Martínez Group aims to make molecular modeling both predictive and routine. New approaches to interactive molecular simulation are being developed, in which users interact with a virtual-reality based molecular modeling kit that fully understands quantum mechanics. New techniques to discover heretofore unknown chemical reactions are being developed and tested, exploiting the many efficient methods that the Martínez group has introduced for solving quantum mechanical problems quickly, using a combination of physical/chemical insights and commodity videogaming hardware.
Quantum Chemistry on the GPUS
TeraChem is a powerful general-purpose quantum chemistry package developed in our group. By exploiting graphical processing units and designing the code from the ground up to expose parallel concurrency, we are able to accelerate Hartree-Fock and DFT calculations by several orders of magnitude over CPU based programs. This allows ab initio quantum mechanical calculations to be routinely performed on extremely large systems.
Tensor Hyper-contraction
The electron repulsion integral (ERI) tensor is a demanding source of computational complexity in many ab initio methods. In the THC approximation, we reduce this fourth-order tensor to a product of five second-order tensors. This new approximation allows ab initio methods to be evaluated with reduced scaling. We have shown that this reduces the scaling to O(N4) for MP2, MP3, CC2, EOM-CC2, and CCSD. Other efforts to increase computational efficiency include the use of the Hubbard type correction to minimal basis sets.
The Ab Initio Nanoreactor
Chemical understanding is driven by the experimental discovery of new compounds and reactivity, and is supported by theory and computation that provide detailed physical insight. The ab initio nanoreactor is a highly accelerated first-principles molecular dynamics simulation of chemical reactions that discovers new molecules and mechanisms without preordained reaction coordinates or elementary steps. Using the nanoreactor, we can find new pathways which highlight the emergence of theoretical and computational chemistry as a tool for discovery.