Quantum-classical effective-modes dynamics of the La->npi* decay in adenine. A quadratic vibronic coupling model D. Picconi,1,2 F. J. Avila Ferrer,1 R. Improta,3 A. Lami,1 F. Santoro1 1Istituto di Chimica dei Composti Organo Metallici del CNR, 2Scuola Normale Superiore di Pisa, 3 Istituto di Biostrutture e Bioimmagini del CNR, Napoli. fabrizio.santoro@iccom.cnr.it Photostability of nucleic acids is ensured by highly efficient decay pathways that operate either on single nucleobases or on oligomers, transforming the electronic excitation into vibrational energy and finally into heat. Based on our previous work on this subject [1,5] in this contribution we deal with the role of n?* in the decay of Adenine derivatives in gas-phase. Potential energy surfaces have been characterized by TD-DFT and diabatized according to a property-based procedure to obtain a quadratic vibronic coupling (QVC) model. The short-time dynamics of the system has been simulated accurately thanks to the development of a hierarchical representation of QVC Hamiltonian [6] that generalizes the original idea proposed by Cederbaum and co. [7] for linear-vibronic coupling (LVC) model. On the ground of such representation, we perform coupled quantum-classical dynamical simulations of the La-> n?* decay in Adenine by treating the coordinates belonging to the first members of the hierarchy at accurate quantum level and the remaining coordinates at classical level. Quantum and classical coordinates and momenta are coupled, and the Schrödinger and Hamilton equations are solved simultaneously. The simulations show that a sensible amount of the La population is transferred to the npi* on a ultrafast time scale. It is shown that the extent of the population transfer is dominated by the dynamics along the coordinates of the first two blocks of the hierarchy (9 coordinates), while the remaining coordinates mainly quench the residual quantum beats of the electronic states populations. [1] R. Improta, V. Barone, A. Lami, F. Santoro, J. Phys. Chem B 113, 14491, 2009 [2] R. Improta, F. Santoro, V. Barone, A. Lami, J. Phys. Chem. A, 113, 15346, 2009 [3] F. Santoro, V. Barone, and R. Improta, Proc Natl. Acad. of Science, USA; 104, 9931, 2007 [4] F. Santoro, V. Barone, R. Improta, J. Am. Chem. Soc. 131, 15232, 2009 [5] D. Picconi, V. Barone, A. Lami, F. Santoro, R. Improta, ChemPhysChem 12, 1957, 2011 [6] D. Picconi, A. Lami and F. Santoro, J. Chem. Phys. 136, 244104, 2012 [7] L. S. Cederbaum, E. Gindesperger, I. Burghardt, Phys. Rew. Lett. 94, 113003, 2005
Quantum-classical effective-modes dynamics of the pipi*/npi* decay in 9H-Adenine. A quadratic vibronic coupling model
R Improta;F Santoro
2013
Abstract
Quantum-classical effective-modes dynamics of the La->npi* decay in adenine. A quadratic vibronic coupling model D. Picconi,1,2 F. J. Avila Ferrer,1 R. Improta,3 A. Lami,1 F. Santoro1 1Istituto di Chimica dei Composti Organo Metallici del CNR, 2Scuola Normale Superiore di Pisa, 3 Istituto di Biostrutture e Bioimmagini del CNR, Napoli. fabrizio.santoro@iccom.cnr.it Photostability of nucleic acids is ensured by highly efficient decay pathways that operate either on single nucleobases or on oligomers, transforming the electronic excitation into vibrational energy and finally into heat. Based on our previous work on this subject [1,5] in this contribution we deal with the role of n?* in the decay of Adenine derivatives in gas-phase. Potential energy surfaces have been characterized by TD-DFT and diabatized according to a property-based procedure to obtain a quadratic vibronic coupling (QVC) model. The short-time dynamics of the system has been simulated accurately thanks to the development of a hierarchical representation of QVC Hamiltonian [6] that generalizes the original idea proposed by Cederbaum and co. [7] for linear-vibronic coupling (LVC) model. On the ground of such representation, we perform coupled quantum-classical dynamical simulations of the La-> n?* decay in Adenine by treating the coordinates belonging to the first members of the hierarchy at accurate quantum level and the remaining coordinates at classical level. Quantum and classical coordinates and momenta are coupled, and the Schrödinger and Hamilton equations are solved simultaneously. The simulations show that a sensible amount of the La population is transferred to the npi* on a ultrafast time scale. It is shown that the extent of the population transfer is dominated by the dynamics along the coordinates of the first two blocks of the hierarchy (9 coordinates), while the remaining coordinates mainly quench the residual quantum beats of the electronic states populations. [1] R. Improta, V. Barone, A. Lami, F. Santoro, J. Phys. Chem B 113, 14491, 2009 [2] R. Improta, F. Santoro, V. Barone, A. Lami, J. Phys. Chem. A, 113, 15346, 2009 [3] F. Santoro, V. Barone, and R. Improta, Proc Natl. Acad. of Science, USA; 104, 9931, 2007 [4] F. Santoro, V. Barone, R. Improta, J. Am. Chem. Soc. 131, 15232, 2009 [5] D. Picconi, V. Barone, A. Lami, F. Santoro, R. Improta, ChemPhysChem 12, 1957, 2011 [6] D. Picconi, A. Lami and F. Santoro, J. Chem. Phys. 136, 244104, 2012 [7] L. S. Cederbaum, E. Gindesperger, I. Burghardt, Phys. Rew. Lett. 94, 113003, 2005I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
