The technique whereby the Raman spectrum of a highly absorbing liquid or solution could be obtained with laser excitation was introduced by Kiefer and Bernstein. Its essential feature is that of rotating the sample at ca. 1500 rpm, by which procedure both thermal decomposition of the absorbing sample and the thermal lens effect are minimized. Modifications to the original arrangement have appeared in which a metal sleeve connects a cylindrical cell to an electrical motor situated at the top of the apparatus. In both arrangements, the laser beam is made to strike the bottom of the cell very near its perimeter, because in this way self-absorption of the scattered light is minimized. The modified system may be adapted for low temperature studies by surrounding the cell with a Dewar and allowing cold nitrogen gas to flow through. Variable temperature rotating liquid cells for Raman spectroscopy have also been described.
R. J. H. Clark, O. H. Ellestad, and P. D. Mitchell, "Rotating Cell for Recording Raman Spectra of Compounds in the Vapor Phase at Elevated Temperatures," Appl. Spectrosc. 28, 575-576 (1974)