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Absolute intensities of the vibration-rotation lines of the CO2 401II←000 band 7734 cm-1 are measured under high-resolution, low-pressure conditions by use of a White-type 25-m base-path, absorption cell together with a 5-m Czerny-Turner spectrometer. The total band intensity SB, the purely vibrational transition moment , and the vibration-rotation interaction constant ζ are calculated from the intensity measurements. The values obtained for these parameters are SB(401II) = (7.06±0.07) × 10-5 cm-2 atm-1293°K, = (3.08±0.03)×10-5 debye, and ζ = (2.5±0.5)×10-4. The intensity of the associated “hot band” 411II←010 is also determined and found to be SB(411II←010) = (0.53±0.02)×10-5 cm-2 atm-1293°K.

Absolute line intensities and self-broadening coefficients have been measured at 197° and 294°K for the 201II ← 000 band of 12C16O2 at about 4978cm-1. The vibration-rotation factor (FVR), the purely vibrational transition moment (∣R(O)∣), and the integrated band intensity (Sband) are deduced from the measurements. The results are: FVR(m)=1+(0.24±0.08)x10-4m+(0.55+0.21)x10-4m2, ∣R(O)∣= (4.340±0.008x10-3 debye, Sband=96372±190cm-1km-1atm-1STP. The results for self-broadening coefficients, as well as for individual vibration-rotation lines, are presented in the text.

The integral band intensity of the pure rotational absorption of SO2 gas has been determined from far-i.r. spectra. From the curve of growth, the value at 298°K is found to be Sob = 35.2±1.5atm-1 -cm-2. The entire set of experimental data has been analyzed using an absorption band model. The derived intensity agrees with that obtained from the curve of growth to be better than 10%. This result should be of value in connection with atmospheric models of the planet Venus.

Line intensities for the P sub P and P sub Q branches of the (2-O) vibrational band of the magnetic dipole electronic transition for the oxygen red system at 6280 A were measured, and the sum of the R sub R and R sub Q branch intensities was taken. A large number of repetitive spectral scans were required for accuracy, because of low absorption values even at optical path lengths from 300 to 600 m. A total of 557 individual measurements of P-branch lines yielded an intensity value for the P-branches, and equivalent widths for 24 spectral scans yielded an intensity value for the R-branch. R-branch to P-branch intensity ratios were taken for the A-band, B-band, and gamma-band (respectively, O-O at 7620 A, 1-O at 6880 A, and 2-O at 6280 A). Intensities for some rotational lines are found, and effects of combined rotation-vibration interaction are probed.

A theoretical fit has been made to laboratory measurements of the 1-0 collisionally induced H2 absorption band over a temperature range of 100-273 K and for densities up to 22 amagats. Both the Birnbaum-Cohen and the MacTaggert-Hunt line shape profiles were used. In addition, an intermolecular potential of either a Lennard-Jones 6-12 or a Morse-spline-van der Waals has been used for each line shape. The best fit resulted in a chi-square of 5%. Line widths have also been derived as a function of temperature. The lifetimes of the states were calculated.

Measurements made at temperatures of 197, 233, and 294°K of the absolute intensities and self-broadening coefficients for the vibration-rotation lines of the 201III←000 band of the 12C16O2 molecule, are reported. From these measurements, values have been derived for the vibration-rotation interaction factor (FVR), the purely vibrational transition moment (|R(O)|), and the intensity (SBand). The results are: EVR(m) = 1+(2.2±0.7)×10−3 m+(5.6±1.6)×10×5m2, |R(0)| = (2.064±0.017)×10−3 debye, SBand = 21,329±69 cm−1 km−1 atm−1STP. The results for the self-broadening coefficients are presented in the text.

A Goody random band model with a Voigt line profile is used to calculate the band absorption of CFCB at various pressures at room and stratospheric (216 K) temperatures. Absorption coefficients and line spacings are computed.

Quantitative measurements of intensities and half-widths were made for individual rotational lines of the atmospheric oxygen B band. The total band intensity, as derived from the line intensity measurements, is 40·8±0·6 cm −1 km −1 atm −1 STP. As had been previously found in this laboratory for the oxygen A band, the relative line intensities conform closely to the rotational distribution calculated by either Schlapp or by Watson. The line half-widths at half-intensity were determined for oxygen self-broadening for the P Q and P P branch lines and for a few R Q and R R branch lines near the band origin, and were found to vary from 0·064 cm −1 atm −1 at J ′ = 1 to 0·042 cm −1 atm −1 at J ′ = 25.

A theoretical fit has been made to our laboratory measurements of the 2-0 collisionally induced H2 absorption band for temperatures of 122 and 273.3 K and at a density of 20 amagats. A Lennard-Jones 6-12 intermolecular potential and a Birnbaum-Cohen line profile have been used. The fit resulted in a chi-square of 0.2%. Line widths have also been derived as a function of temperature. The lifetimes of the states have been calculated.

The absolute intensities of the 8-12 micron bands from Freon 11 (CFCl3) were measured at temperatures of 294 and 216 K. Intensities of the bands centered at 798, 847, 934, and 1082 per cm are all observed to depend on temperature. The temperature dependence for the 847 and 1082 per cm fundamental regions is attributed to underlying hot bands; for the nu2 + nu5 combination band (934 per cm), the observed temperature dependence is in close agreement with theoretical prediction. The implication of these results on atmospheric IR remote-sensing is briefly discussed.

Quantitative measurements of intensity and half-width have been made for over 30 lines in each of the C12O162 bands of the 1·6 μ tetrad. The total band intensities, derived from the line intensity measurements, for the (30°1)I, (30°1)II, (30°1)III, and (30°1)IV bands are 127, 1050, 1070, and 122 cm-1 km-1 atm-1 STP, respect ively. The observed rotational line intensity distribution of the (30°1)III band was found to depart slightly from the Boltzmann distribution. A satisfactory fit to the observed distribution was obtained by applying a weak vibration- rotation interaction. The widths of the lines of the (30°1)IV band are found to be 50 per cent larger than those of the other members of this tetrad.

The quantitative intensity of the weak CO2 triad in the 1 μ spectral region has been measured. Integrated R-branch intensities were obtained by using pressure broadening techniques with absorbing paths up to 4·8 km-atm. The R-branch intensities for the transitions 20°3«00°0, 12°3«00°0, and 04°3«00°0 are 1·27, 3·50, and 0·59 cm−1 km−1 atm−1 S.T.P., respectively. Intensities and half-widths of the J4 through J22 lines in the P-branch of the 12°3«00°0 transition have been determined.

Atmospheric oxygen A band individual rotational lines intensities and half widths measurements

An example is presented which demonstrates the importance of using physically realistic derivatives of the intermolecular potential when fitting pressure-induced spectra. The use of nonrealistic derivatives may mask second-order temperature effects in the theory. As the temperature decreases, the intermolecular potential may have an important angular dependence.

Comments on Hunt's (1972) conclusion that the phase variation of lines in the 7820- and 7883-A CO2 bands is due to the presence of two scattering layers in the Venusian atmosphere. It is shown that the increase of equivalent width with phase between 0 and 90 deg noted by Hunt in the data by Gray Young et al. (1971) does not necessarily require a two-layer model of scattering in the Venusian atmosphere and that this increase may be due to the strong backward lobe in the Venusian cloud phase function. Hunt, in a reply, notes that Regas et al. incorrectly use in their analysis Hansen's (1969) data which are for a homogeneous planetary atmosphere, while Hunt used an inhomogeneous model of the Venusian atmosphere. In addition, further evidence to support Hunt's claim for a multilayered structure of the upper Venusian clouds is presented.