Rotational Spectrum of the AsH(2) Radical in Its Ground State, Studied by Far-Infrared Laser Magnetic Resonance.

The rotational spectrum of AsH(2) in its ground &Xtilde;(2)B(1) electronic state has been recorded using a far-infrared laser magnetic resonance spectrometer. The AsH(2) radical was produced inside the spectrometer cavity by the reaction of arsine (AsH(3)) with fluorine atoms. Hyperfine splittings from both (75)As and (1)H nuclei were observed, and analysis of the spectra has yielded accurate values for rotational, hyperfine, and Zeeman parameters. Copyright 2000 Academic Press.

Far-Infrared Laser Magnetic Resonance Spectroscopic Study of the nu(2) Bending Fundamental of the CCN Radical in Its &Xtilde;(2)Pi(r) State.

Bending vibration-rotation transitions between the (010) µ(2)Sigma(-) and (000) (2)Pi(r) vibronic states of the CCN radical in its ground electronic state have been observed using far-infrared laser magnetic resonance (FIR LMR) spectroscopy. Thirteen FIR laser lines were used to record 769 resonances. The LMR data, combined with previous data, were used to determine vibrational, Renner-Teller, fine-structure, rotational, hyperfine, and molecular g-factor parameters using a least-squares fitting routine. The model used was an N(2) effective Hamiltonian modified to include the Renner-Teller effect explicitly in a (2)Pi electronic state. The band origin for the (010) µ(2)Sigma(-) <-- (000) &Xtilde;(2)Pi(r) transition was determined to be 179.598176 +/- 0.000067 cm(-1). The spin-orbit splitting in the ground state was refined and the complete set of (14)N-hyperfine parameters determined for the first time.

Far-Infrared Rotational and Fine-Structure Transition Frequencies and Molecular Constants of 14NO and 15NO in the X2Pi (v = 0) State.

We have made highly accurate measurements of the absorption spectrum of the 14NO and 15NO isotopomers of nitric oxide in the far-infrared. Pure rotational transitions up to J" = 3712 within the 2Pi1/2 and 2Pi3/2 spin components and several 2Pi3/2 <-- 2Pi1/2 fine-structure transitions were recorded within the ground vibrational state. A least-squares fit to these data combined with some lambda-doubling and rotational transitions measured by previous workers has resulted in accurate values for the rotational, fine, and hyperfine parameters of these two isotopomers. Most of the far-infrared transitions reported here have an experimental uncertainty of about 20 kHz and will be useful for astronomers and atmospheric scientists studying this important molecule. The more accurate calculated frequencies will also be useful as spectroscopic calibration standards. Copyright 1999 Academic Press.

Optically Pumped FIR Laser Lines from CH3OH: New Laser Lines, Frequency Measurements, and Assignments.

We report the identification and characterization of eight new FIR laser lines from methanol (CH3OH) in the range 48.4 to 453.7 µm pumped by sequence and hot bands of a cw CO2 laser. Frequency measurements for most of the new FIR laser lines and from previously reported ones were obtained in the range 0.6-6.8 THz with a one-sigma reproducibility of two parts in 10(7). We propose an assignment of energy levels for two of the new laser lines and for five pumped by 10R(46) previously reported. The high frequency lines with absorption centers outside of the tuning range of the CO2 laser pump showed doublets. These were used to evaluate the offsets of the CO2 absorption transitions.

Frequencies of Optically Pumped Sub-Doppler Far-Infrared Laser Lines of Methanol.

Sub-Doppler signals from the gain curves of four lines of a transversely pumped far-infrared methanol laser were used to stabilize the frequencies of the laser. The frequencies of four of the strongest FIR laser lines (70, 119, 123, and 570 µm) were measured. Lasers locked to these lines have a frequency reproducibility of a few parts in 10(8) and an uncertainty of less than 30 kHz. Copyright 1998 Academic Press.

Sub-Doppler Frequency Measurements of 15NH3 Laser Transitions

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C-13 Methanol Far-Infrared Laser: Newly Discovered Lines, Predictions, and Assignments

We report 25 new laser lines from 13CH3OH methanol when pumped by a cw CO2 laser. The majority of the lines are pumped by the 10R (regular) and 10SR (sequence) bands of the CO2 laser. Two are pumped by the 9HP(20) hot-band CO2 line. We measured 22 laser frequencies in this molecule, 19 from new lines and three from previously reported lines. We also remeasured and corrected the frequency of the 9P(44) pumped line as 3 378 404.87 MHz (88.738 µm). We assigned two lines-10SR(17), 77.5758 cm-1 and 10R(50), 119.3020 cm-1-and predicted other potential far-infrared laser lines with these two pumps. Copyright 1998 Academic Press.

Far-Infrared Rotational Spectra of ZnH and ZnD in the X2Sigma+ (v = 0) State

Several rotational transitions of zinc hydride and deuteride within the v = 0 level of the X2Sigma+ state have been measured in both electron spin components over the ranges N" = 2 to 10 for ZnH and N" = 9 to 21 for ZnD. A least-squares fit to these data in combination with low-N microwave data measured by other workers has resulted in improved values of the rotational, fine, and hyperfine structure constants. The values of the proton hyperfine constants are discussed in the context of a molecular orbital analysis of zinc hydride. Copyright 1997 Academic Press. Copyright 1997Academic Press