On the effect of ultraviolet radiation on water vapor absorption of submillimeter waves

The submillimeter absorption spectra of pure water vapor and a water vapor + dry air mixture are experimentally studied under the conditions of illumination of the gas sample by ultraviolet (UV) radiation. The measurements were carried out by a vacuum echelette spectrometer in the wave number range 21.5–56 cm⁻¹ with spectral resolution 0.4–0.9 cm⁻¹, using a DRT-375 mercury-vapor discharge lamp as the source of UV radiation. In contrast to the results of similar experiments performed by other researchers, the data presented here demonstrate the absence of a noticeable effect of the UV radiation on the absorption spectra of the gas samples used. Radiophysical Research Institute, Nizhny Novgorod, Russia. Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Radiofizika, Vol. 41, No. 5, pp. 581–587, May, 1998.