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We determined accurate He-broadening parameters and collisional cross sections for the P(2) line in the fundamental band of CO at room temperature and at intermediate temperatures down to 11.5 K. We also determined a precise value for the temperature dependence of the line-broadening parameter on (T)−nwith nequal to 0.548±0.010. Our results validate the microwave results for the J=1 to J=2 rotational transitions measured over the same range of temperatures which were reported previously by Beaky et al.(1996, J. Chem. Phys.105, 3994–4004).

A new generation of infrared instrumentation incorporating tunable diode lasers has been developed for application to industrial analysis and process monitoring problems. Specific advantages of tunability in the mid-infrared, high spectral resolution, and milliwatt range power outputs are discussed and comparisons made to conventional infrared instrumentation. Examples of applications in the areas of on-line process monitoring and quality control of silicone-based polymers, smokestack effluent monitoring, nondestructive quality control testing of quartz-halogen lamps, and quantitative analysis of aqueous based solutions are presented. Conclusions are drawn indicating the potential for further applications in these and related areas.

The absolute intensities of 188 vibration-rotational spectral lines of transitions to the vibrational states ν2= 1 and ν5= 1 of 12CH3F have been measured with a diode laser. By taking into account the mixing of the rovibrational wavefunctions of both vibrational states by Coriolis and l-type interactions (Papoušek, Papoušková, Ogilvie, Pracna, Civiš, and Winnewisser. J. Mol. Spectrosc.153,145-166 (1992 )), the values of the vibrational transition moments and their relative signs were determined by a least squares fit to the experimental data: 〈0, 00|μz| 1, 00〉 = ϵ × (0.01106 ± 0.00017)D and〈0, 00|μx|0, 1±1〉 = ϵ × (0.02173 ± 0.00005)D where ϵ = ±1.

This paper presents a review of several applications of tunable diode laser technology requiring high sensitivity or high precision. The paper outlines technical developments which have led to a reduction in laser noise and an improvement in laser stability, both of which are critical to the task of achieving high signal-to-noise ratios in tunable diode applications. Sophisticated tunable laser systems are described which are being used to collect important data which are used in developing an understanding of the processes responsible for the annual ozone depletion. Stable isotope ratio measurements requiring low noise and high long-term stability and low-temperature collisional cooling experiments requiring low noise are also described. The list of references appropriate to these discussions is comprehensive.

We report the infrared measurement of rotational and translational temperatures for CH3F in the gas phase with a rotational temperature of approximately 16 K. This measurement is accomplished by extending the collisional cooling technique originally developed for the microwave spectral region to the infrared. We measured an RQ(J, 0) feature centered at approximately 1475 cm−1in the ν5band of CH3F. The rotational temperature was determined by measuring relative intensities of low-Jtransitions and comparing these results to those predicted by the rotational partition function. We utilized measurements of the absorption linewidth to calculate a translational temperature of 19 K.

The absolute intensities of 300 vibration-rotation absorption lines associated with transitions from the ground vibrational state to the vibrational states ν2= 1 and ν5= 1 of 12CH3F were measured with a tunable diode laser.

Self and air broadening coefficients were obtained for vibration-rotation transitions in the ν2and ν5bands of 12CH3F. Dependence of the air and self broadening parameters upon the rotational quantum number, J, were also derived for unblended lines. The data reported here show no sip of a dependence on the Kquantum number for the self broadening coefficient.