Simulating surface-enhanced Raman optical activity using atomistic electrodynamics-quantum mechanical models

Dhabih V. Chulhai, Lasse Jensen

Research output: Contribution to journalArticle

15 Citations (Scopus)

Abstract

Raman optical activity has proven to be a powerful tool for probing the geometry of small organic and biomolecules. It has therefore been expected that the same mechanisms responsible for surface-enhanced Raman scattering may allow for similar enhancements in surface-enhanced Raman optical activity (SEROA). However, SEROA has proved to be an experimental challenge and mirror-image SEROA spectra of enantiomers have so far not been measured. There exists a handful of theories to simulate SEROA, all of which treat the perturbed molecule as a point-dipole object. To go beyond these approximations, we present two new methods to simulate SEROA: the first is a dressed-tensors model that treats the molecule as a point-dipole and point-quadrupole object; the second method is the discrete interaction model/quantum mechanical (DIM/QM) model, which considers the entire charge density of the molecule. We show that although the first method is acceptable for small molecules, it fails for a medium-sized one such as 2-bromohexahelicene. We also show that the SEROA mode intensities and signs are highly sensitive to the nature of the local electric field and gradient, the orientation of the molecule, and the surface plasmon frequency width. Our findings give some insight into why experimental SEROA, and in particular observing mirror-image SEROA for enantiomers, has been difficult.

Original languageEnglish (US)
Pages (from-to)9069-9079
Number of pages11
JournalJournal of Physical Chemistry A
Volume118
Issue number39
DOIs
StatePublished - Oct 2 2014

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optical activity
Electrodynamics
quantum electrodynamics
Molecules
Enantiomers
enantiomers
molecules
Mirrors
mirrors
dipoles
Biomolecules
Charge density
Tensors
Raman scattering
quadrupoles
Electric fields
tensors
Raman spectra
gradients
Geometry

All Science Journal Classification (ASJC) codes

  • Physical and Theoretical Chemistry

Cite this

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Simulating surface-enhanced Raman optical activity using atomistic electrodynamics-quantum mechanical models. / Chulhai, Dhabih V.; Jensen, Lasse.

In: Journal of Physical Chemistry A, Vol. 118, No. 39, 02.10.2014, p. 9069-9079.

Research output: Contribution to journalArticle

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