Structure of Low-Lying Excited States of Guanine in DNA and Solution: Combined Molecular Mechanics and High-Level Coupled Cluster Studies

Karol Kowalski,Marat Valiev

doi:10.1155/2007/85978

Abstract

High-level ab-initio equation-of-motion coupled-cluster methods with singles, doubles, and noniterative triples are used, in conjunction with the combined quantum mechanical molecular mechanics approach, to investigate the structure of low-lying excited states of the guanine base in DNA and solvated environments. Our results indicate that while the excitation energy of the first excited state is barely changed compared to its gas-phase counterpart, the excitation energy of the second excited state is blue-shifted by 0.24 eV.

Highlights

Despite their high numerical overhead, the high-level abinitio methods continue to provide strong evidence for a proper inclusion of the excited-state correlation effects in biomolecular systems
(3) Multiscale approaches that integrate ab-initio methods with coarse-grained representations such as molecular mechanics enable a realistic description of large scale systems at finite temperature and pressure conditions
In our previous work [10], we have shown that integration of high-level ab-initio methods with molecular dynamics simulations can provide an efficient and accurate way to study the thermodynamics of excited states

Summary

Introduction

Despite their high numerical overhead, the high-level abinitio methods continue to provide strong evidence for a proper inclusion of the excited-state correlation effects in biomolecular systems. In our previous work [10], we have shown that integration of high-level ab-initio methods with molecular dynamics simulations can provide an efficient and accurate way to study the thermodynamics of excited states.

Results

Conclusion