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Characterization and Surface‐Enhanced Raman Spectroscopy of Alkali Metal Sols
Author(s) -
Bozlee B.,
Clark S.,
Marr C.,
Slaughter S.,
McWatters M.,
Choi Y.,
Garrell R. L.
Publication year - 1996
Publication title -
journal of raman spectroscopy
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.748
H-Index - 110
eISSN - 1097-4555
pISSN - 0377-0486
DOI - 10.1002/(sici)1097-4555(199601)27:1<75::aid-jrs929>3.0.co;2-e
Subject(s) - raman spectroscopy , analytical chemistry (journal) , raman scattering , alkali metal , chemistry , extinction (optical mineralogy) , particle (ecology) , spectral line , spectroscopy , mineralogy , optics , physics , oceanography , organic chemistry , chromatography , quantum mechanics , astronomy , geology
Colloidal suspensions of Li, Na, K, Rb and Cs were prepared in diethyl ether. The effective sizes of particle aggregates were estimated by comparison of experimental visible extinction spectra with calculated spectra using the full equations of Mie scattering. The extinction spectra of Cs sols demonstrate unusual blue shifting as particle aggregation proceeds. The blue‐shifted band is assigned to the transverse resonance of a linear string of Cs particles. Surface‐enhanced Raman (SER) spectra are reported for Na, K and Rb sols. Observation of an OH stretching band (3585 cm −1 ) on the Na sol and growth of the SER bands as moisture is introduced to the Na and K sols strongly suggest that the bands derive from alkali metal hydroxides on the metal surfaces. When a trace of D 2 O is present in the Na sol a new SER band at 2640 cm −1 is observed, and is assigned to the OD stretch of surface NaOD. The Raman excitation spectrum for the 290 cm −1 SER band on Na is compared with the extinction band of the Na sol. The result is found to be in good qualitative agreement with the electromagnetic theory of surface‐enhanced Raman scattering.