Difference frequency generation spectroscopy as a vibrational optical activity measurement tool

Sangheon Cheon, Minhaeng Cho

Research output: Contribution to journalArticlepeer-review

5 Citations (Scopus)

Abstract

Vibrational optical activity (VOA) of chiral molecules in condensed phases can be studied by using vibrational circular dichroism and Raman optical activity measurement techniques. Recently, IR-vis sum frequency generation has shown to be an alternative VOA measurement method. Such a three-wave-mixing method employing a polarization modulation technique can be a potentially useful VOA measurement tool. Here, a theoretical description of difference frequency generation (DFG) employing circularly polarized visible radiations is presented. Frequency scanning to obtain a VOA-DFG spectrum is achieved by controlling the difference between the two electronically nonresonant incident radiation frequencies. If the two incident beams are linearly polarized and their polarization directions are perpendicular to each other, one can selectively measure the all-electric-dipole-allowed chiral component of the DFG susceptibility. In addition, by using circularly polarized beams and taking the DFG difference intensity signal, which is defined as the difference between left and right circularly polarized DFG signals, additional chiral susceptibility components originating from the electric quadrupole transition can be measured. The DFG as a novel VOA measurement technique for solution samples containing chiral molecules will therefore be a useful coherent spectroscopic tool for determining absolute configuration of chiral molecules in condensed phases.

Original languageEnglish
Pages (from-to)2438-2445
Number of pages8
JournalJournal of Physical Chemistry A
Volume113
Issue number11
DOIs
Publication statusPublished - 2009 Mar 19

ASJC Scopus subject areas

  • Physical and Theoretical Chemistry

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