Far-Infrared Rotational Spectrum of ArD+

Rotational transition frequencies of ArD+ were measured with an accuracy of a few hundred kilohertz in the 0.95-4.7 THz region, using a tunable far-infrared radiation source. Effective rotational parameters B, D, and H were determined for the ground vibrational state. The observed frequencies were combined with the previous data on all isotopic species of protonated argon ion to improve the mass-independent Dunham parameters Ukl, DeltaArkl, and DeltaHkl. 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.

Analysis of Rotational Transitions in Excited Vibrational States of Propionitrile (C2H5CN).

We have observed rotational transitions of propionitrile (C2H5CN) in the 8-200 GHz region and assigned 208 transitions with J

Frequency Measurement of Pure Rotational Transitions of H217O and H218O from 0.5 to 5 THz.

Frequencies of pure rotational transitions of isotopic species of water, H217O, and H218O were measured in the 1-5 THz region with a high-precision far-infrared spectrometer using a tunable radiation source. Measured frequencies of more than 100 spectral lines for each species provide an excellent frequency standard for the far-infrared region. Molecular parameters based on a Watson-type Hamiltonian have been obtained to reproduce the observed frequencies. Copyright 1999 Academic Press.

Tunable far-infrared spectroscopy extended to 9.1THz.

We synthesized tunable far-infrared radiation at frequencies higher than 9 THz (300 cm (-1)) by mixing CO(2) laser, (15)NH(3) laser, and microwave radiation in a W-Co metal-insulator-metal diode. We used this farinfrared radiation to accurately measure torsion-rotation transitions of CH(3)OH in the 8-9-THz region. We also measured the frequency of the aP(7, 3) (15)NH(3) laser transition.

Tunable Far-Infrared Spectroscopy of 82KrD+, 84KrD+, 86KrD+, and 82KrH+

Pure rotational spectra of isotopic species of protonated krypton 82KrD+, 84KrD+, 86KrD+, and 82KrH+ were observed in the 0.75-3.5 THz region, using a tunable far-infrared radiation source. Rotational parameters B, D, and H of these molecular ions were determined. By analyzing the observed frequencies with the previous data on all the isotopic species, the mass independent Dunham parameters Ukl, DeltaKrkl, and DeltaHkl have been improved. Copyright 1998 Academic Press.

Sub-Doppler Frequency Measurements of 15NH3 Laser Transitions

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Extension of tunable far-infrared spectroscopy to 7.9THz.

We generated tunable far-infrared radiation by mixing CO(2) -laser,(15)NH(3) -laser, and microwave radiations in a W-Co metal-insulator-metal diode. We used this far-infrared radiation to measure accurately the torsion-rotation transitions of CH(3)OH in the 6-8-THz region.

Cystic cavernous hemangioma of the liver.

We report an unusual case of multilocular cystic cavernous hemangioma of the liver. The patient was a 61-year-old woman without liver disfunction but who had multicystic mass lesions in the liver. Although cavernous hemangiomas are usually accurately diagnosed by the various imaging modalities, our case showed atypical features.