A quantum mechanical description of nuclei, rather than a typical classical one, is required to obtain quantitative accuracy of the time-dependent properties of a molecular system. Our group’s work focuses on the combination of quantum statistics with classical dynamics via Feynman’s path-integral framework. We investigate the underlying theory of quantum statistics-classical dynamics methods and formulate new methods based on novel approximations. Recent successes in the group include the development of ‘Matsubara dynamics’ [1], in which minimal approximations are made to recover quantum-Boltzmann conserving classical dynamics and serves as the underlying framework of the popular Ring Polymer Molecular Dynamics (RPMD) and Centroid Molecular Dynamics (CMD) methods. More recently, a new method has emerged called Quasicentroid Molecular Dynamics (QCMD) [2], that is formulated in curvilinear space, thereby removing some of the computational artefacts found in RPMD and CMD.
My PhD work focuses on theoretical and methodological development of QCMD. Unlike the other methods, QCMD does not naturally generalise to arbitrary molecules and doing so is difficult. However, the reason for wanting to do so is clear; QCMD is the superior path-integral method for generating IR spectra, as demonstrated with calculations on condensed phase water and ice. In a recent publication, we successfully extended QCMD to ammonia-like geometries, again showing that it produces superior IR spectra across a range of temperatures [3, 4].
Prior to joing the Althorpe group, I completed an MPhil in Scientific Computing at the CSC and I am currently a member of the Computational Methods in Material Science CDT.
1. T. J. H. Hele, M. J. Willatt, A. Muolo, and S. C. Althorpe, J. Chem. Phys. 142, 134103 (2015).
2. G. Trenins, M. J. Willatt, and S. C. Althorpe, J. Chem. Phys. 151, 054109 (2019).
3. C. Haggard, V. Sadhasivam, G. Trenins and S. Althorpe, J. Chem. Phys. 155, 174120 (2021).
4. G. Trenins, C. Haggarda and S. Althorpe, J. Chem. Phys. 157, 174108 (2022)