Engineering topics

Zink, L. R.

Publications and source records attributed to Zink, L. R..

8 records

NASA NTRS1992

Far-infrared self-broadening in methylcyanide - Absorber-perturber resonance

Using tunable far-infrared spectrometers with high-frequency stability and accuracy, the self-pressure broadening and shift of CH3CN are measured. Evidence of absorber-perturber resonance effects on the collisional line shape are obtained. This tests the theoretical model and its possible improvements and also allows predictions of broadening and shift for a large class of molecules. Moreover, the resonance effect produces a theoretical temperature dependence of self-broadening that is different from what is commonly assumed.

Buffa, G.↗

NASA NTRS1991

Far infrared laser frequencies of CH3OD and N2H4

The frequencies of 26 laser lines with wavelengths between 57 and 534 microns are measured in the optically pumped laser gases CH3OD and N2H4. A pair of 12CO2 lasers are employed as a frequency standard for the heterodyne frequency measurements. As the measurements are oriented toward spectroscopic applications of FIR lasers where dense, broad, frequency coverage is essential, every strong pump absorption of the two molecules for new lines that might be made to lase by varying the laser gas pressure and the tuning of the pump laser are investigated.

Radford, H. E.↗

NASA NTRS1990

Laboratory measurements for the astrophysical identification of MgH

A tunable far-infrared spectrometer has been used to observe the pure rotational spectrum of MgH in a DC discharge of H2 with magnesium. The frequencies of the hyperfine components of the N = 1 - 0 transition are predicted to an estimated accuracy of + or - 350 kHz, which should be sufficient for the astrophysical identification of this species.

Zink, L. R.↗

NASA NTRS1990

Accurate frequency of the 119 micron methanol laser from tunable far-infrared absorption spectroscopy

High-accuracy absorption spectroscopy of CH3OH in the far infrared is discussed. In addition to 22 transitions in the ground state, the frequency of the (n, tau, J, K), (0, 1, 16, 8) to (0, 2, 15, 7) transition in the nu5 excited vibrational level, which is responsible for the laser emission at 119 microns, was measured. The measured frequency is 2,522,782.57(10) MHz at zero pressure, with a pressure shift of 6.1(32) kHz/Pa (0.805/420/ MHz/torr). An accurate remeasurement of the laser emission frequency has also been performed, and the results are in good agreement.

Inguscio, M.↗

NASA NTRS1988

Frequency measurement of the J = 1-0 rotational transition of HD

The frequency of the astronomically important J = 1-0 rotational transition of HD at 2.7 THz (90/cm) has been measured with tunable FIR radiation with an accuracy of 150 kHz. This frequency is now known to sufficient accuracy for use in future astrophysical heterodyne observations of HD in planetary atmospheres (reported by Bezard et al., 1986) and in the interstellar medium (reported by Bussoletti et al., 1975).

Evenson, K. M.↗

NASA NTRS1987

Sub-Doppler tunable far-infrared spectroscopy

The first experimental observations of sub-Doppler linewidths in a cell made using tunable far-infrared radiation are reported. A double-resonance scheme has been used, combining CO2-laser infrared radiation with tunable far-infrared radiation to observe a sub-Doppler line shape in an excited vibrational state of CH3OH.

Inguscio, M.↗

NASA NTRS1987

NO2 heterodyne frequency measurements with a tunable diode laser, a CO laser transfer oscillator and CO2 laser standards

Heterodyne frequency measurements have been made on selected groups of nitrogen dioxide rovibronic transitions between 1580.8 and 1650.7/cm. The groups are separated by 7 to 10/cm, and the intent is to provide a limited (and interim) calibration table for the region. In addition to a table of measured frequencies in the region, figures of spectra in the vicinity of the measured lines are included to provide a map for identifying the transitions measured.

Zink, L. R.↗

NASA NTRS1986

Laboratory measurement of the rotational spectrum of the OH radical with tunable far-infrared research

Rotational and fine-structure transitions between the low rotational levels of the OH radical in its X 2Pi state have been observed in absorption in the laboratory. It has thus been possible to measure the frequencies of these transitions directly. The observations were made with tunable far-infrared radiation generated by mixing two chosen CO2 laser frequencies in a metal-insulator-metal diode; the far-infrared difference frequency was radiated from the diode's whisker antenna. The measurements have an accuracy of a few hundred kHz. They both confirm and improve on the best previous estimates, which were obtained by extrapolation of laser magnetic resonance data.

Brown, J. M.↗