G. Moruzzi

The Fourier spectrum of CH3OH: The region between 8 and 40 cm−1

Abstract The experimental Fourier spectrum of CH 3 OH has been investigated between 8 and 40 cm −1 . Good agreement was found between the experimental measurements and the results of the computational routines available up to now when low J values ( J ≲ 10) are involved. At higher J , the line assignments are possible by means of Taylor expansions of the energy levels. A catalog of almost 1500 lines, two-thirds of which have been assigned, is presented.

CH3OH laser line assignments and frequency predictions

Abstract By utilizing the results of high resolution infrared (IR) and far-infrared (FIR) spectroscopy we discuss the reported assignments of more than 300 FIR laser lines in optically-pumped CH 3 OH. The analysis has been done both by feeding each IR-pump/FIR-laser transition system into the computer fit program described in previous works, and by combining the CO 2 laser optical pumping frequency, the FIR laser frequencies and the IR and FIR spectroscopic measurements to construct closed frequency loops. When the energy balance of a loop is found to be zero to within experimental uncertainty the assignments of all sides of the loop are supported. In addition, improved accuracies by one to two orders of magnitude for the FIR laser frequencies, and predictions for new laser lines have been obtained for a number of systems from loop combination differences.

Geniculate Unit Responses to Sine-Wave Photic Stimulation during Wakefulness and Sleep

The oscillation in firing rate of units of the lateral geniculate body in response to stimulation with sine-wave light was studied in unanesthetized cats with the brainstem sectioned immediately in front of the fifth nerve (pretrigeminal preparation). During wakefulness, as indicated by behavior and by electroencephalograms, the time course of the oscillation in firing rate followed very closely the change in intensity of sine-wave light. During synchronized sleep there was no such relationship.

Frequency measurement of the K = 6 asymmetry splittings in CH3OH

Abstract Tunable far-infrared spectroscopy was applied to the study of small asymmetry doublings in the ground vibrational, ground torsional state of CH 3 OH. For the first time splittings of K = 6 states were measured. The splitting constant was found to be S (6) = 9(1) × 10 −19 MHz, corresponding to a splitting of 360(35) KHz for J = 29 and 240(25) kHz for J = 28.

High-resolution synchrotron-based Fourier transform spectroscopy of in the 120–350 cm−1 far-infrared region

The Fourier transform spectrum of the isotopologue of methanol has been recorded in the 120–350 cm−1 far-infrared region at a resolution of 0.00096 cm−1 using synchrotron source radiation at the Canadian Light Source. The study, motivated by astrophysical applications, is aimed at generating a sufficiently accurate set of energy level term values for the ground vibrational state to allow prediction of the centres of the quadrupole hyperfine multiplets for astronomically observable sub-millimetre transitions to within an uncertainty of a few MHz. To expedite transition identification, a new function was added to the Ritz program in which predicted spectral line positions were generated by an adjustable interpolation between the known assignments for the and isotopologues. By displaying the predictions along with the experimental spectrum on the computer monitor and adjusting the predictions to match observed features, rapid assignment of numerous sub-bands was possible. The least squares function of the Ritz program was then used to generate term values for the identified levels. For each torsion-K-rotation substate, the term values were fitted to a Taylor-series expansion in powers of J(J + 1) to determine the substate origin energy and effective B-value. In this first phase of the study we did not attempt a full global fit to the assigned transitions, but instead fitted the sub-band J-independent origins to a restricted Hamiltonian containing the principal torsional and K-dependent terms. These included structural and torsional potential parameters plus quartic distortional and torsion–rotation interaction terms.