Earle K. Plyler

ROTATION-VIBRATION SPECTRA OF DEUTERATED WATER VAPOR

Spectra of heavy water have been obtained under high resolution between 1.25—4.1μ (2400—8000 cm—1). Approximately 4500 lines have been measured, and the majority of them analyzed into ten bands of D2O and nine bands of HDO. The analysis is described in some detail, spectra of all bands are shown and a partial table of lines and a complete table of energy levels are presented. The vibration‐rotation constants are derived and compared with those of H2O.

Infrared Spectrum of Hydrogen Sulfide

The absorption of hydrogen sulfide has been investigated in the 8 μ region under high resolution. The absorption has been analyzed as a B‐type band and assigned as the (n1,n2,n3)=(0,1,0) band. The resulting inertial constants agree well with those predicted from previously analyzed bands. The best values of the constants for this band are, v0=1182.68 cm—1, A=10.724, B=9.211, C=4.670. The knowledge of this band center, together with previously determined frequencies, enable the evaluation of the constants in the quadratic expression for the vibrational energy. A second‐order resonance was found which arises from the near coincidence of the frequencies v1 and v3.

Vibration-Rotation Bands of Ammonia. IV. The Stretching Fundamentals and Associated Bands near 3 μ

High‐resolution spectra of NH3, yielding 1800 lines between 3060–3580 cm−1, are presented. Analysis of the ν3 fundamental is complete through J′=9 and presents no unexpected features. Resolution of the K substructure in the ν1 fundamental shows that several perturbations are present. The most important of these, involving a Fermi resonance with the parallel component of 2ν4, and a Coriolis resonance with its perpendicular component, are clarified. Lines in both components of 2ν4 are identified through J′=6, and a strong Coriolis interaction between the l=0 and l=2 states is observed and discussed.

INFRARED SPECTRA OF HYDROGEN CYANIDE AND DEUTERIUM CYANIDE

The infrared spectra of HCN and DCN have been investigated in the region 1900 to 8000 cm‐1. Twenty‐two bands of HCN and eighteen bands of DCN were measured. The newly measured bands together with previously known bands enable a complete determination of the vibrational anharmonic constants for the two molecules. A third‐order resonance between levels of the type (v1,v2l,v3) and (v1+3, v2l, v3 — 2) is shown to be present in the HCN vibrational energy‐level system.

ROTATION-VIBRATION CONSTANTS OF ACETYLENE

The study of the absorption spectrum previously reported has been extended to include the 1900- to 2200- and the 4400- to 6750-cm−1 regions. Rotational analysis provides 20 states from which the following constants are determined: α1 = 6.82, α2 = 6.30, α3 = 5.60, α4 = −1.30, α5 = −2.20 × 10−3 cm−1 and Be = 1.18240 cm−1. This value was used with Be values for C2HD and C2D2 to determine the bond length of re(C−H)=1.0603 and re(C≡C)=1.2034A.A total of 46 states was available, from this and other work, to determine a set of vibrational constants. About one-half of the 23 constants have been determined with acceptable precision. The remaining constants are still in doubt due, primarily, to resonances.

Vibration-Rotation Bands of N 2 O†*

The spectrum of nitrous oxide has been measured with a high-resolution grating spectrometer in the region from 2395 to 3510 cm−1. Long absorbing paths were used in a heated cell, so that it was possible to observe many of the weaker bands, including those with lower vibrational levels ν2, 2ν20, 2ν22, and ν1. Accurate values of the rotational constants have been obtained, including the l-type doubling and variations with v and l of the centrifugal stretching constant. These have been correlated with other data to obtain improved values of the molecular constants, with particular attention to the Fermi interaction. Other weak interactions are observed and discussed.

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.

Molecular Parameters of Ethane

The combination band ν2+ν6 of ethane at 2754 cm—1 has been studied under high resolution. The value of B0 has been found to be 0.66310±0.00007 cm—1. When this value is combined with values of A0 of C2H6 and B0 for C2D6 determined in other studies, the following parameters are obtained: r0(C–C) = 1.536 A, r0(C–H) = 1.108 A, and ∠C–C–H = 110.1°.

Ethane Carbon‐Carbon Distance Obtained from Infrared Spectra

The parallel band of ethane at 2753 cm—1 and the parallel band of ethane‐d6 at 2816 cm—1 have been observed and analyzed. The resultant values of B for C2H6 and C2D6 are 0.6637 cm—1 and 0.4598 cm—1, respectively. From these B values the C–C distance is found to be 1.534 A and the quantity (rCC/2+rCHcosθ)2+rCH/22sin2θ=1.866 A where θ=180−∠HCC. If the rCH value of methane (1.093 A) is assumed, the ∠HCC is 109° 45′.

Precise Measurements in the Infrared Spectrum of Carbon Monoxide

New measurements have been made in the CO infrared spectrum in both emission and absorption, using a 15,000‐line/inch grating spectrograph and a 7200‐line/inch vacuum grating spectrograph. High precision in wavelength determinations was obtained by superimposing on the spectra emission lines in higher order of Hg, Kr, and A discharges. The measurements are believed accurate to ±0.02 cm−1. The observed lines in absorption are those of the 2–0 and 3–0 bands of C12O16, between R 30—P 29 and R 9—P 16, respectively; 27 lines of C13O16 and 10 lines of C12O18 have also been measured. In emission from oxy‐acetylene and CO–O2 flames, over 300 lines in the 2–0, 3–1, 4–2, and 5–3 bands have been identified between 4360 and 4000 cm−1. The emission bands form heads in the R branch near J=50, and the 2–0 band shows resolved lines out to J=46 in both P and R branches.The new measurements are in good agreement with earlier results at low quantum numbers, but show discrepancies at high numbers which result in slightly dif...