PRESSURE-INDUCED LINE SHIFTS AND WIDTHS OF $O_{3}$ BROADENED BY $N_{2}$ AND BY AIR

Author Institution: Atmospheric Sciences Division, Mail Stop 401A, NASA Langley Research Center; Physics Department, College of William and Mary,; Atmospheric Sciences Division, Mail Stop 401A, NASA Langley Research Center; Physics Department, College of William and MaryFourier transform spectra of $O_{3}$ broadened by approximately 100 to 300 Torr $N_{2}$ or dry air have been analyzed to determine both halfwidths and shifts for over 60 lines in the $9-\mu m$ region. The spectra were recorded at $0.005 cm^{-1}$ resolution with the McMath FTS at the National Solar Observatory on Kitt Peak, and halfwidths and line positions were determined using a nonlinear least-squares spectral fitting technique. Unshifted line positions were determined from additional FTS spectra of nearly pure $O_{3}$ at low pressure, and all spectra were calibrated using well-known $H_{2}O$ lines near $7.5 \mu m$. Additional broadening measurements were made for 13 of the $O_{3}$ lines using the tunable diode laser spectrometer at NASA Langley Research Center. The TDL results agree with the FTS measurements within 4\%. Most of the lines measured belong to the R branch of the $\nu_{1}$ band of $O_{3}$, covering the range of rotational quantum numbers $8 \le J^{\prime\prime} \le 45$ and $0 \le K^{\prime\prime}_{a} \le 11$. For both air and $N_{2}$ broadening, the majority of observed halfwidths fall within the range 0.065 to $0.09 cm^{-1}$ atm$^{-1}$, and the shifts vary between $+0.004 cm^{-1} atm^{-1}$ and $-0.008 cm^{-1}$ atm$^{-1}$. A strong dependence on rotational quantum numbers $J^{\prime\prime}$ and $K_{a}^{\prime\prime}$ is observed for both halfwidths and shifts