Ab initio direct semiclassical molecular dynamics

A multiple coherent states time-averaging [1] semiclassical initial value representation (MC-TA-SC-IVR) method for spectra calculations is presented.[2, 3] The method is implemented for ab initio semiclassical simulations, i.e. a direct dynamics approach, and it is shown to faithfully reproduce all kind of quantum effects, including ZPEs, anharmonicities, tunneling splittings, resonances [4] and vibrational eigenfunctions.[5] This on-the-fly approach is useful in particular for complex systems,[5, 6] where the elaboration of a pre-computed potential energy surface can turn into a formidable task. I will show that the method can deal with molecules with multiple wells and as complex as glycine. [1] A. L. Kaledin and W. H. Miller, J. Chem. Phys. 118, 7174 (2003) [2] M. Ceotto, S. Atahan, S. Shim, G. F. Tantardini, and A. Aspuru-Guzik, Phys. Chem. Chem. Phys. 11, 3861 (2009) [3] M. Ceotto, S. Atahan, G. F. Tantardini, and A. Aspuru-Guzik, J. Chem. Phys. 130, 234113 (2009) [4] M. Ceotto, D. Dell'Angelo, and G. F. Tantardini, J. Chem. Phys. 133, 054701 (2010) [5] M. Ceotto, S. Valleau, G. F. Tantardini, and A. Aspuru-Guzik, J. Chem Phys. 134, 234103 (2011) [6] M. Ceotto, G. F. Tantardini, and A. Aspuru-Guzik, J. Chem. Phys. 135, 214108 (2011) [7] M. Ceotto, Y. Zhuang, and W.L. Hase, J. Chem. Phys. 138, 054116 (2013)