New cryogenic apparatus for FT-IR spectroscopic studies

Cryogenic Fourier transform infrared (PT-IR) spectroscopy, being an effecti ve technique in improving the spectral resolution and signal-to-noise ratio , is utilized in our group. However, we have found the traditional cryogeni c apparatus inconvenient in the following aspects: (1) The system does not work very well in preventing moisture/frost from condensing on the salt win dows or samples. (2) The indirect way of cooling using a metal cold finger limits the efficiency of the system, We have designed a new cryogenic appar atus. The apparatus is composed of a cooling stage and a measuring stage, I n the cooling stage, the sample is directly immersed in Liquid nitrogen, In the measuring stage, the sample is lifted just above the surface of liquid nitrogen, and the FT-IR spectrum is recorded. The dry cold nitrogen gas ev aporated from liquid nitrogen forms a protective layer surrounding the samp le and prevents moisture from condensing on the sample. Thus, neither vacuu m nor salt windows are needed in cryogenic spectroscopic experiments using this method. The experimental results show that our method is effective in cryogenic FT-IR spectroscopic studies.