Absorption Spectrum of Crystals at Low Temperatures. I : The Effect of Temperature on Spectrum of Benzene and its Monoderivatives

We observed the temperature effect of absorption bands in benzene and its monoderivatives, namely monochlorbenzene, monobrombenzene and toluene. There were a displacement of the bands toward the shorter wave-length and a narrowing of the bands, when the temperature was decreased. About benezene band we studied theoretically the effect of temperature and obtained considerably good results which agreed well with experiments, the band shift is proportional to thermal energy and the half-intensity breadth proportional to a root of thermal energy