Assessing the accuracy of many-body expansions for the computation of solvatochromic shifts

Abstract

In this work, a computationally fast and simple scheme for calculating vertical excitation energies based on a many-body expansion is reviewed. It consists of a two-body expansion where each of the energy terms is computed with embedding in a point charge field representing the environment. The neglect of two-body polarisation energy terms is evaluated, as it allows for a compact energy expression, and avoids parameterisation of the solute. The solvatochromic shifts for the acetone and acrolein molecules are investigated, both in microsolvated clusters as well as in solution. It is found that the scheme is unable to correctly describe Rydberg states, but succeeds in closely reproducing the many-body effects involved in the π → π* excitation of acrolein in water.

Keywords:

• many body
• spectra
• solution
• acetone
• acrolein

Acknowledgements

Financial support from the Fundação para a Ciência e Tecnologia (grant reference SFRH/BPD/38447/2007) is gratefully acknowledged.

Notes

Note

Supplementary material can be viewed online.