Line parameter measurements of trace gases in the near infrared region

The absorption spectra of CO ₂ , CO, and N ₂ O in the near infrared region were measured with a high-resolution Fourier transform spectrometer to examine the uncertainties of the line parameters of spectroscopic databases. The line strengths and half-widths of these molecules were determined by a nonlinear least squares technique. We compared our results with the values compiled in the HITRAN databases. Large differences between the measured line strengths and the compiled ones in the HITRAN databases were found for the weak bands of each molecule. The Herman-Wallis coefficient was determined for the first overtone band of CO. Self-broadened half-widths of CO ₂ and N ₂ O agreed with the HITRAN96 values; while self-broadened half-widths of CO were different from the HITRAN96 values. N ₂ - and O ₂ -broadened half-widths of CO were very close to the values previously reported by others.