L. R. Blaine

Velocity of Light from the Molecular Constants of Carbon Monoxide

By infrared spectroscopy precise measurements of the wavelengths of forty-three rotational lines in the CO absorption band at 4.67 μ were made. Fifteen lines from J=32 to J=52 in the P branch were measured from the emission spectrum of CO. These data were reduced by the method of least squares, and values of the rotational constants, B0 and D0, of CO were calculated. A second, slightly less precise set of measurements over approximately the same range of J values was similarly reduced, and combined estimates of the constants were obtained. Using the resulting value of B0 with the value obtained from microwave frequency measurements, the velocity of light was estimated to be 299 792 km/sec. The estimated standard deviation of this value is 6 km/sec.

Infrared Spectrum of Carbonyl Sulfide

Fourteen bands of carbonyl sulfide have been observed between 1 and 5.5 μ. The rotational fine structure of the bands has been analyzed and the values of the molecular constants determined. From the average ΔF2 values of the 8 best bands, B0=0.20288±0.00002 cm—1 and D0=(4.08±0.52)×10—8 cm—1, in excellent agreement with the microwave determinations. Several constants in the quadratic expression for the vibrational energy are evaluated, but Fermi resonance between levels of the type (v1,v2l,v3) and (v1 — 1, v2l+2, v3) rule out a complete determination from the presently available bands. It is shown that the previously suggested Fermi resonance between v3 and 4v20 is so small that it is not detected in this work.

The emission spectrum of OH trom 2·8 to 4·1 μ

The emission spectrum of on oxyacetylene flame has been measured from 2·8 to 4·1 μ. The most prominent features of the spectrum in this region arise from the 3 → 2, 2 → 1, and 1 → 0 vibrational transitions of OH in the ground electronic state. Most of the observed emission can be accounted for by the P branches of these three transitions, although transitions in other branches are observed for some of the vibrational bands. Strong emission by water vapour precludes observation of the OH spectrum at wavelengths shorter than 2·8 μ.