Significant Contributions of the Albrecht’s A Term to Nonresonant Raman Scattering Processes
2015 (English)In: Journal of Chemical Theory and Computation, ISSN 1549-9618, E-ISSN 1549-9626, Vol. 11, no 11, 5385-5390 p.Article in journal (Refereed) PublishedText
The Raman intensity can be well described by the famous Albrecht’s Raman theory that consists of A and B terms. It is well-known that the contribution from Albrecht’s A term can be neglected without any loss of accuracy for far-off resonant Raman scattering processes. However, as demonstrated in this study, we have found that this widely accepted long-standing assumption fails drastically for totally symmetric vibration modes of molecules in general off-resonant Raman scattering. Perturbed first-principles calculations for water molecule show that strong constructive interference between the A and B terms occurs for the Raman intensity of the symmetric O-H stretching mode, which can account for ∼40% of the total intensity. Meanwhile, a minor destructive interference is found for the angle bending mode. The state-to-state mapping between Albrecht’s theory and perturbation theory allows us to verify the accuracy of the widely employed perturbation method for the dynamic/resonant Raman intensities. The model calculations rationalized from water molecule with the bending mode show that the perturbation method is a good approximation only when the absolute energy difference between the first excited state and the incident light is more than five times greater than the vibrational energy in the ground state.
Place, publisher, year, edition, pages
American Chemical Society (ACS), 2015. Vol. 11, no 11, 5385-5390 p.
IdentifiersURN: urn:nbn:se:kth:diva-181970DOI: 10.1021/acs.jctc.5b00761ISI: 000364614000031ScopusID: 2-s2.0-84946893555OAI: oai:DiVA.org:kth-181970DiVA: diva2:902917
FunderSwedish Research Council
QC 201602122016-02-122016-02-112016-02-12Bibliographically approved