Surface sum-frequency vibrational spectroscopy of nonpolar media

Shumei Sun; Chuanshan Tian; Y Ron Shen

doi:10.1073/pnas.1505438112

Surface sum-frequency vibrational spectroscopy of nonpolar media

Proc Natl Acad Sci U S A. 2015 May 12;112(19):5883-7. doi: 10.1073/pnas.1505438112. Epub 2015 Apr 27.

Authors

Shumei Sun¹, Chuanshan Tian², Y Ron Shen³

Affiliations

¹ Department of Physics, State Key Laboratory of Surface Physics, and Key Laboratory of Micro- and Nano-Photonic Structures, Fudan University, Shanghai 200433, China;
² Department of Physics, State Key Laboratory of Surface Physics, and Key Laboratory of Micro- and Nano-Photonic Structures, Fudan University, Shanghai 200433, China; Collaborative Innovation Center of Advanced Microstructures, Fudan University, Shanghai 200433, China; and cstian@fudan.edu.cn yrshen@calmail.berkeley.edu.
³ Department of Physics, State Key Laboratory of Surface Physics, and Key Laboratory of Micro- and Nano-Photonic Structures, Fudan University, Shanghai 200433, China; Department of Physics, University of California, Berkeley, CA 94720 cstian@fudan.edu.cn yrshen@calmail.berkeley.edu.

Abstract

Sum-frequency generation spectroscopy is surface specific only if the bulk contribution to the signal is negligible. Negligible bulk contribution is, however, not necessarily true, even for media with inversion symmetry. The inevitable challenge is to find the surface spectrum in the presence of bulk contribution, part of which has been believed to be inseparable from the surface contribution. Here, we show that, for nonpolar media, it is possible to separately deduce surface and bulk spectra from combined phase-sensitive sum-frequency vibrational spectroscopic measurements in reflection and transmission. The study of benzene interfaces is presented as an example.

Keywords: bulk contribution; electric-quadrupole contribution; nonpolar media; sum-frequency spectroscopy; surface structure.

Publication types

Research Support, Non-U.S. Gov't
Research Support, U.S. Gov't, Non-P.H.S.