抄録
A low temperature microspectrophotometer consisted of a Hitachi EPS-3T spectrophotometer and a specially designed stainless-steel low temperature box containing a microscope was constructed.The box could be evacuated and was equipped with a stainless-steel cylinder that could reserve ca 500 ml liquid nitrogen.The liquid nitrogen flows from this cylinder to a specially designed cooling stage of the microscope through a copper pipe.As the microscope a Nippon Kogaku POH polarizing microscope was used together with an Olympus MO 90 reflecting objective (90×) or a Zeiss-Jena reflecting objective (40×).
Using this apparatus, visible and ultraviolet absorption spectra of crystalline barium permanganate, potassium chromate, and potassium dichromate were measured at room temperature and at low temperature (90 K).Spectra obtained at the low temperature were much better resolved than those obtained at room temperature and the lower energy band of potassium dichromate was split into two bands.Maxima of the absorption bands were shifted to the blue and their half-widths decreased, in crystals compared to those in solution and also in crystals at the low temperature compared to those at room temperature.
