Communication: Spectroscopic phase and lineshapes in high-resolution broadband sum frequency vibrational spectroscopy: resolving interfacial inhomogeneities of "identical" molecular groups.
The ability to achieve sub-wavenumber resolution (0.6 cm(-1)) and a large signal-to-noise ratio in high-resolution broadband sum-frequency generation vibrational spectroscopy (HR-BB-SFG-VS) allows for the detailed SFG spectral lineshapes to be used in the unambiguous determination of fine spectral features. Changes in the structural spectroscopic phase in SFG-VS as a function of beam polarization and experimental geometry proved to be instrumental in the identification of an unexpected 2.78 ± 0.07 cm(-1) spectral splitting for the two methyl groups at the vapor/dimethyl sulfoxide (DMSO, (CH(3))(2)SO) liquid interface as well as in the determination of their orientational angles.
William R. Wiley Environmental Molecular Sciences Laboratory, Pacific Northwest National Laboratory, Richland, Washington 99352, USA.
Luis
L
Velarde
Xian-yi
XY
Zhang
Zhou
Z
Lu
Alan G
AG
Joly
Zheming
Z
Wang
Hong-fei
HF
Wang