Tunable diode laser measurement of self and foreign broadening and shift versus temperature of seven ammonia transitions of the v(sub 2) band

摘要

Self broadening and self shift coefficients have been measured as a function of temperature in the range from 200 to 400 K for seven ammonia transitions in the v(sub 2) band near 900 cm(sup -1). Among these, one (near 921 cm (sup -1)) has been used to study the broadening and shift coefficients induced by several foreign gas as N(sub 2), O(sub 2), Air, H(sub 2), Ar, He, as a function of temperature from 180 to 400 K. The results have been compared with semiclassical calculations relying on the impact approximation. The main results are that the modifies Anderson-Tsao-Curnutte theory describes very well the self broadening but has some limitations for self shift and foreign gas measurements. Moreover, this theory does not agree well with the empirical laws describing the temperature behaviours, especially when wide temperature ranges are involved. On the other hand these empirical laws are completely at odd in those cases when the shift coefficient changes its sign versus temperature as it's observed in this work.