Diode laser measurements of linestrength and temperature-dependent lineshape parameters of H2O-, CO2-, and N2-perturbed H2O transitions near 2474 and 2482 nm

Abstract

Absorption lineshapes for two unresolved H2O doublets near 4029.52 and 4041.92cm−1 were measured at high-resolution in a heated static cell using two distributed-feedback diode lasers. Measurements were acquired for H2O, CO2, and N2 perturbers over a temperature and pressure range of 650–1325K and 2–760Torr, respectively. Strong collisional narrowing effects were observed in CO2 and N2, but not in pure H2O. The Galatry profile was used to infer collisional-broadening and -narrowing coefficients and their respective temperature dependence for CO2 and N2 perturbers. The collisional-broadening and -narrowing coefficients for CO2 perturbers were found to decrease with increasing temperature in a similar manner. For N2 perturbers, the collisional-broadening coefficients increased with temperature while the collisional-narrowing coefficients decreased with increasing temperature. Self-broadening coefficients were inferred from Voigt profile fits and are compared with HITEMP 2010. The linestrengths of 17H2O transitions are also reported.