VARIABLE-TEMPERATURE PRESSURE BROADENING OF THE 4(1,4)-3(2,1) TRANSITION OF H2O BY O-2 AND N-2

The O2 and N2 pressure-broadening parameters of the 4(1,4)-3(2,1) rota tional transition in the ground vibrational state of H2O have been mea sured in the temperature range between 100 and 520 K. Above 250 K the measurements were made in an equilibrium cell. Below 250 K a cell, whi ch uses collisional cooling to circumvent the temperature limits impos ed by the vapor pressure of the sample gas, was used. The data were fi tted to an exponential temperature-dependence for data above 150 K wit h resultant n values of 0.81(3) for O2 and 0.70(3) for N2, where the e ntries in parentheses represent the error in the last significant figu re of the parameter. Below 150 K the measured pressure-broadening para meters are smaller than those calculated using these values of n.