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.

Multielectron effects in high harmonic generation in N_{2} and benzene: Simulation using a non-adiabatic quantum molecular dynamics approach for laser-molecule interactions

Rent:

Rent this article for

USD

10.1063/1.4718590

### Abstract

A mixed quantum-classical approach is introduced which allows the dynamical response of molecules driven far from equilibrium to be modeled. This method is applied to the interaction of molecules with intense, short-duration laser pulses. The electronic response of the molecule is described using time-dependent density functional theory (TDDFT) and the resulting Kohn-Sham equations are solved numerically using finite difference techniques in conjunction with local and global adaptations of an underlying grid in curvilinear coordinates. Using this approach, simulations can be carried out for a wide range of molecules and both all-electron and pseudopotential calculations are possible. The approach is applied to the study of high harmonic generation in N_{2} and benzene using linearly polarized laser pulses and, to the best of our knowledge, the results for benzene represent the first TDDFT calculations of high harmonic generation in benzene using linearly polarized laser pulses. For N_{2} an enhancement of the cut-off harmonics is observed whenever the laser polarization is aligned perpendicular to the molecular axis. This enhancement is attributed to the symmetry properties of the Kohn-Sham orbital that responds predominantly to the pulse. In benzene we predict that a suppression in the cut-off harmonics occurs whenever the laser polarization is aligned parallel to the molecular plane. We attribute this suppression to the symmetry-induced response of the highest-occupied molecular orbital.

© 2012 American Institute of Physics

Received 21 November 2011
Accepted 01 May 2012
Published online 17 May 2012

Article outline:

I. INTRODUCTION

II. THE NON-ADIABATIC QUANTUM MOLECULAR DYNAMICS APPROACH

III. TIME-DEPENDENT DENSITY FUNCTIONAL TREATMENT OF THE ELECTRON DYNAMICS

IV. ADAPTIVE CURVILINEAR COORDINATES

A. Globally adaptive curvilinear coordinates

B. Locally adaptive curvilinear coordinates

C. The Kohn-Sham equations in adaptive curvilinear coordinates

V. IMPLEMENTATION OF THE METHOD

A. Discretization of the Kohn-Sham equations using finite differences

B. Parallelization

C. Time propagation

1. Time propagation of the Kohn-Sham equations

2. Time propagation of the ionic equations of motion

D. Calculation of the initial state

1. Propagation in imaginary time

2. Thick-restarted Lanczos (TRLan) method

3. The Chebyshev filtered subspace iteration (CheFSI) method

E. Calculation of the Hartree potential

F. Treatment of the exchange-correlation potential

G. Treatment of the electron-ion potentials

1. All-electron calculations

2. Pseudopotential calculations

H. Treatment of the laser-electron interaction

I. Wavefunction splitting

VI. RESULTS

A. Initial state generation: Accuracy and efficiency

1. Efficiency of the eigensolvers

2. Accuracy of the energy eigenstates using locally adaptive grids

B. Multielectron and orientation effects in molecular HHG

1. Multielectron and orientation effects in HHG in N_{2}

2. Multielectron and orientation effects in HHG in benzene

VII. CONCLUSIONS

/content/aip/journal/jcp/136/19/10.1063/1.4718590

http://aip.metastore.ingenta.com/content/aip/journal/jcp/136/19/10.1063/1.4718590

Article metrics loading...

/content/aip/journal/jcp/136/19/10.1063/1.4718590

2012-05-17

2014-04-18

Full text loading...

### Most read this month

Article

content/aip/journal/jcp

Journal

5

3

Commenting has been disabled for this content