The calculation of the semiclassical propagator is a Monte Carlo integration over classical trajectories. This can be accelerated either by importance sampling or parallelization. In the first case, 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,[4] resonances [5] and vibrational eigenfunctions.[6] This on-the-fly approach is useful in particular for complex systems,[7, 8] where the elaboration of a pre-computed potential energy surface can turn into a formidable task. In the second case, SC-IVR can be implemented for GPUs. [9] An almost constant scaling for GPU calculations versus a linear scaling for CPU ones is found respect to the number of trajectories. Issues and limitations related to the GPU implementation will be discussed. [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] R. Conte, A. Aspuru-Guzik, and M. Ceotto, J. Phys. Chem. Lett. 4, 3407-3412 (2013) [5] M. Ceotto, D. Dell'Angelo, and G. F. Tantardini, J. Chem. Phys. 133, 054701 (2010) [6] M. Ceotto, S. Valleau, G. F. Tantardini, and A. Aspuru-Guzik, J. Chem Phys. 134, 234103 (2011) [7] M. Ceotto, G. F. Tantardini, and A. Aspuru-Guzik, J. Chem. Phys. 135, 214108 (2011) [8] M. Ceotto, Y. Zhuang, and W.L. Hase, J. Chem. Phys. 138, 054116 (2013) [9] D. Tamascelli, F. D'Ambrosio, R. Conte, and M. Ceotto, in progress
Relatore al Seminar Quantum Dynamics presso il "Max-Planck-Institut fur Physik Komplexer Systeme" in Dresden con un intervento dal titolo "Ab initio Semiclassical molecular dynamics for CPU and GPU hardware"(2014 Jan 14).
Relatore al Seminar Quantum Dynamics presso il "Max-Planck-Institut fur Physik Komplexer Systeme" in Dresden con un intervento dal titolo "Ab initio Semiclassical molecular dynamics for CPU and GPU hardware"
2014
Abstract
The calculation of the semiclassical propagator is a Monte Carlo integration over classical trajectories. This can be accelerated either by importance sampling or parallelization. In the first case, 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,[4] resonances [5] and vibrational eigenfunctions.[6] This on-the-fly approach is useful in particular for complex systems,[7, 8] where the elaboration of a pre-computed potential energy surface can turn into a formidable task. In the second case, SC-IVR can be implemented for GPUs. [9] An almost constant scaling for GPU calculations versus a linear scaling for CPU ones is found respect to the number of trajectories. Issues and limitations related to the GPU implementation will be discussed. [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] R. Conte, A. Aspuru-Guzik, and M. Ceotto, J. Phys. Chem. Lett. 4, 3407-3412 (2013) [5] M. Ceotto, D. Dell'Angelo, and G. F. Tantardini, J. Chem. Phys. 133, 054701 (2010) [6] M. Ceotto, S. Valleau, G. F. Tantardini, and A. Aspuru-Guzik, J. Chem Phys. 134, 234103 (2011) [7] M. Ceotto, G. F. Tantardini, and A. Aspuru-Guzik, J. Chem. Phys. 135, 214108 (2011) [8] M. Ceotto, Y. Zhuang, and W.L. Hase, J. Chem. Phys. 138, 054116 (2013) [9] D. Tamascelli, F. D'Ambrosio, R. Conte, and M. Ceotto, in progress
Pubblicazioni consigliate
I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
