Massive Parallelization of Exact Quantum Dynamics Calculations: Computing (ro)vibrational states for real molecular applications

Texas Tech University, Lubbock TX

Investigators

Abstract

Lionel (Bill) Poirier of Texas Tech University is supported by an award from the Theory, Models and Computational Methods program in the Chemistry division to develop and test massively parallel high performance computing codes that enable exact quantum dynamics (QD) rovibrational spectroscopy calculations for larger and more challenging molecular applications than are currently possible. The award is co-funded by a pilot program in OCI promoting the reuse of Cyberinfrastructure (CI) elements. This capability is valuable for various dynamical, kinetic, and statistical modeling endeavors, for which accurate knowledge of rovibrational states and partition function of the molecular species involved is often vitally important. A novel feature of this research over previous quantum dynamics efforts is use of massive parallelization. Much of the requisite cyberinfrastructure, i.e., parallel linear algebra codes, developed by the PI previously, is already in place. To assess the performance, scalability, and broad applicability of the parallel codes, two extremely challenging, but very different, benchmark molecular applications are being considered, both well beyond the capabilities of the current state of the art in exact QD methods. The first is isomerization in neon clusters. The second is intramolecular hydrogen atom transfer in malonaldehyde, as a prototype for proton transfer in intermediate-barrier enzyme catalysis, and more complex biological systems. The scale of the proposed calculations is designed to be adjustable, and will be varied up to the maximum capacity of the 1000-plus-core Chemistry Computation Cluster (CCC) available to the PI. The PI and his research group are devoting much effort to make their computer codes, and exact quantum dynamics in general, easier for "non experts" to use, by developing a user-friendly "front end". They are also hosting training workshop at the Texas Tech (TTU) Department of Chemistry and Biochemistry, for TTU, regional and other users. The parallelQD codes are being updated and disseminated through the CCC. These software tools greatly extend the complexity of systems that can be studied quantum dynamically, while simultaneously cyber-enabling a broader cross section of the chemical dynamics community to perform such calculations on their own.