Low Temperature Cell for Measurement of Raman Spectra

Abstract

For the measurement of Raman spectra at variable temperature, low temperature cells cooled by nitrogen or helium are currently used; such cells are usually provided with an evacuated jacket in order to prevent condensation of moisture on the cold cell walls.^1–3 The construction of such cells is rather complicated and, besides that, relatively large energy losses are inevitable due to the passage of the beam through the cell jackets. For the measurement of Raman spectra of liquids with He-Ne laser excitation, we have been using with considerable success a very simple arrangement in which the cylindrical cell is placed as near as possible to the entrance slit of the spectrograph, with the laser beam passing through the axis of the tube parallel to the entrance slit. For the same basic arrangement, we have also constructed a nitrogen cooled low temperature cell. Condensation of moisture on the cell is prevented by a stream of dry cooling nitrogen. The same principle has been used by us for some time in variable temperature studies of infrared spectra.⁴