New FIR laser lines and frequency measurements for optically pumped CD3OH

Twenty new cw FIR laser lines in CD₃OH, optically pumped by a CO₂ laser, are reported. The frequencies of 39 of the stronger laser lines were measured relative to stabilized CO₂ lasers with a fractional uncertainty, as determined by the reproducibility of the FIR frequency itself, of 2 parts in 10⁷.Contribution of the U.S. Government, not subject to copyright.     

Comparison of XYZ Model Fitting Functions for 111Cd in In3La

The XYZ model describes the interaction between nuclear probes and an electric field gradient that fluctuates among three orthogonal directions. The model presents a means to calculate the perturbation function that represents spectra obtained using perturbed angular correlation spectroscopy. Three analytic approximations of the perturbation function have been developed previously, and they are evaluated in the present paper in the context of Cd jumping among In-lattice sites in In₃La.     

CO laser stabilization using the optogalvanic Lamb-dip

Frequency stabilization of the CO laser using a CO lamb-dip is achieved in the range from 5.0–6.3 m. The CO saturation signal is obtained from a low-pressure discharge in absorption and is detected using optogalvanic, detection. The frequency stability and reproducibility has been verified to be better than 100 kHz; this is an improvement of more than one order of magnitude compared with locking techniques using CO laser gain profiles.Alexander von Humboldt Awardee from National Bureau of Standards, Boulder, Colorado, USA     

A Novel Dimeric Eremophilane from Ligularia virgaurea spp. oligocephala

A novel dimeric eremophilane, ligulolide B, was isolated from the alcoholic extract of the whole plant of Ligularia virgaurea spp. oligocephala. The structure was elucidated by various spectroscopic methods including intensive 2D NMR techniques （^1H-^1H COSY, gHMQC, gHMBC and ^1H-^1H NOESY） and HR-ESI-MS.     

New far infrared laser lines obtained by optically pumping13CD3OD

We have obtained laser action on 34 far infrared lines for the first time in fully deuterated methyl alcohol with the¹³C isotope (¹³CD₃OD), and we have measured the frequency of 13 lines. The molecule was pumped by a cw CO₂ laser. We have measured the wavelength, the relative polarization, the relative intensity of most lines, the frequency, and the CO₂ pump frequency offset of the strongest lines. The new lines are distributed in the wavelength region from 75.27 m to 464.7 m.Supported in part by a joint grant with the U.S. National Science Foundation grant # INT 80-19014 and the Brazilian Conselho Nacional de Pesquisas (CNPq).     

New FIR laser lines and frequency measurements in CD3OD

Twenty-four new submillimeter laser lines in fully deuterated methyl alcohol (CD₃OD) in the wavelength range from 52 to 328 m have been obtained in a Fabry-Perot FIR resonator by optically pumping the methanol with a cw CO₂ laser. We have made accurate wavelength measurements and have determined the relative polarization of most of the known CD₃OD laser lines. The frequencies of 13 of the strongest lines were also measured.Contribution of the U.S. Government, not subject to copyright.     

Modeling complex diffusion mechanisms in L1 2 -structured compounds

We report on a procedure developed to create stochastic models of hyperfine interactions for complex diffusion mechanisms and demonstrate its application to simulate perturbed angular correlation spectra for the divacancy and 6-jump cycle diffusion mechanisms in L1₂-structured compounds.     

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.