No data available.

Please log in to see this content.

You have no subscription access to this content.

No metrics data to plot.

The attempt to load metrics for this article has failed.

The attempt to plot a graph for these metrics has failed.

Hierarchical transformation of Hamiltonians with linear and quadratic couplings for nonadiabatic quantum dynamics: Application to the ππ*/*n*π* internal conversion in thymine

Rent:

Rent this article for

USD

10.1063/1.4729049

### Abstract

We face with the general problem of defining a reduced number of effective collective coordinates to describe accurately the short-time nonadiabaticdynamics of large semirigid systems, amenable to a description in terms of coupled harmonic potential energy surfaces. We present a numeric iterative protocol to define a hierarchical representation of the Hamiltonian taking into account both linear and quadratic intra- and inter-state couplings (QVC, quadratic vibronic coupling model), thus generalizing the method introduced recently in the literature [E. Gindensperger, H. Köppel, and L. S. Cederbaum, J. Chem. Phys.126, 034106 (2007)]10.1063/1.2426342 for the linear vibronic coupling (LVC) model. This improvement allows to take into account the effect of harmonic frequency changes and Duschinsky mixings among the different electronic states, providing a route to upgrade the models for nonadiabatic harmonic systems to those nowadays routinely used for the simulation of vibronic spectra of adiabatic systems (negligible nonadiabatic couplings). We apply our method to the study of ππ* → *n*π* internal conversion in thymine, analysing the differences in LVC and QVC predictions both for the absorptionspectrum and the dynamics of electronic populations.

© 2012 American Institute of Physics

Received 18 March 2012
Accepted 29 May 2012
Published online 25 June 2012

Acknowledgments: The authors acknowledge the support of Italian MIUR (PRIN 2008 “Time”) and IIT (Project IIT-Seed “Helyos”).

Article outline:

I. INTRODUCTION

II. HIERARCHY OF EFFECTIVE OSCILLATORS ACCORDING TO THE QUADRATIC VIBRONIC COUPLING MODEL OF POTENTIAL

A. Generalized form of Lanczos tridiagonalization algorithm

B. Definition of the cumulants of the spectrum

C. Construction of effective hierarchically coupled coordinates for a QVC Hamiltonian

III. APPLICATION: THE INTERNAL CONVERSION IN THYMINE

A. Definition of the potential energy surfaces

B. Computational details

IV. RESULTS AND DISCUSSION

A. Quantum dynamics of the ππ*/*n*π* population transfer

1. Adiabatic vs. vertical approaches

B. Autocorrelation functions

C. Nonadiabaticabsorption spectra

V. CONCLUSION

/content/aip/journal/jcp/136/24/10.1063/1.4729049

http://aip.metastore.ingenta.com/content/aip/journal/jcp/136/24/10.1063/1.4729049

Article metrics loading...

/content/aip/journal/jcp/136/24/10.1063/1.4729049

2012-06-25

2014-04-19

Full text loading...

### Most read this month

Article

content/aip/journal/jcp

Journal

5

3

Commenting has been disabled for this content