Line Broadening and the Temperature Exponent of the Fundamental Band in CO-N(2) Mixtures

We have measured the width, Gamma, of many P and R lines of the fundamental vibration-rotation band of CO perturbed by N(2) at 348 K and pressures of about 50 kPa. We have also extended the measurements made earlier at room temperature. The broadening coefficients, gamma = Gamma/pressure, were obtained with an accuracy of 0.3% by fitting with a Lorentzian, a Voigt, and an empirical lineshape model that blends together a hard-collision model and a speed-dependent Lorentzian profile. In all cases the results are represented by an empirical exponential power law polynomial in the line number, m. Combining the data at the two temperatures yields the exponent n in the scaling law gamma(T(1))/gamma(T(2)) = (T(1)/T(2))(-n), as a function of line number. The broadening coefficients and the variation of the temperature exponent line number are compared with theory. In addition, the line-mixing parameters are also reported at 348 and 301 K. Copyright 1999 Academic Press.