J. V. V. Kasper

Infrared absorption spectrum of C2H radical with color center laser

P. Q. and R branches are studied for C2H free radicals. (AIP) P. Q. and R branches are studied for C2H free radicals. (AIP)

Microwave optical double resonance spectrum of NH2. V. Hyperfine structure of the u state

The hyperfine structure of the u state of NH2, a rovibronic level in the ? 2B1 manifold [tentatively assigned as 220, J=3/2, ? 2B1(0,13,0)] has been obtained from an analysis of the strong microwave optical double resonance (MODR) signals which occur between the u state and the J=1/2 and 3/2 spin components of 110 in ?2 A1Π (0,10,0). The hyperfine assignment was verified with a new technique that we have chosen to call microwave modulated saturation (MMS) spectroscopy. The similarity of the hyperfine splittings in u due to the H nuclear spin with those of the 220, J=3/2 rotational level of the ? 2B1(0,0,0) state supports the assignment of u to a highly excited vibrational state of ? 2B1. The hyperfine splittings due to the 14N nucleus were found to be about 1 MHz. These splittings are considerably smaller than those of 220 X 2B1(0,0,0) (which are about 6–10 MHz). This difference has been attributed to the fact that the hyperfine coupling constants of (0,13,0) must be averaged over a large amplitude bendin...

Color-center laser kinetic spectroscopy: observation of the a 1 Δ NH vibrational fundamental

The vibrational fundamental of a1Δ NH formed by 193-nm excimer-laser photolysis of gaseous HN3 has been observed using a color-center laser. The high degree of rotational excitation resulting from the photolysis, corresponding to a temperature of ∼10 000 K, allows high-order centrifugal distortion constants to be determined. The frequencies of the 35 observed lines and the centrifugal distortion constants determined from them are reported.

Restricted Rotation in Solid Deuteromethanes

The theory of Nagamiya for restricted rotation in solid methane is extended to all of the partially deuterated species and applied to the experimental heat‐capacity data of Colwell, Gill, and Morrison, which show anomalously high values in the range below 4°K. Agreement with these data is obtained for reasonable values of the energy parameters; also the total entropy of each anomaly is predicted.

Computer controlled IR spectrometer using a color center laser

A high resolution IR spectrometer for the2.2-3.3\mum range has been developed using a computer controlled CW color center laser. Computer control makes possible single-frequency scans of up to 100 cm-1with a resolution determined by the cavity mode spacing (250 MHz) and continuous high resolution scans (linewidth below 1 MHz) over 1 cm-1ranges. The laser spectrometer has been tested on the NO overtone band at 2.68 μm.

Microwave modulated saturation spectroscopy

By combining intermodulated fluorescence saturation spectroscopy with microwave optical double resonance, a new experimental laser spectroscopy technique, microwave modulated saturation (MMS) spectroscopy, has been developed. This technique has been used to simplify the complex 14N and proton hyperfine structure observed by saturation spectroscopy of NH2[110, J=3/2←220, J=5/2, ?2A1π (0,10,0) ←?2B1(0,0,0)]. This simplification made possible a complete assignment of the hyperfine energy levels. A population model of these experiments has been developed.

Computer controlled cw laser spectrometer

A computer controlled cw UV-visible dye laser source for spectroscopic use has been developed. Computer control facilitates both continuous single-frequency scanning and data acquisition. With 4 W of Ar-ion laser pump power, such a spectrometer can generate in excess of 1 W of cw single-frequency power in the visible and up to 1 mW in the UV by using extracavity nonlinear optical mixing. The laser spectrometer has been tested by performing high-resolution measurements of the fluorescence spectrum of I(2) in the visible and of the absorption spectrum of SO(2) in the UV.

Multiwavenumber linearized diode laser spectra by overlapping frequency scans

A method for producing diode laser spectroscopy scans which are several wavenumbers long, linear in frequency, and readily and accurately calibrated from reference spectra is described. The laser itself is current scanned under computer control over short segments (as is normally done) and such overlapping segments are linearized and pieced together to provide the final scan.

Color center laser spesctroscopy of free radicals

High resolution infrared spectra of free radicals are obtained when an electrical discharge occurs through Ar over a coating of polyacetylene. A computer‐controlled color center laser was used as the excitation source. (AIP)

High Sensitivity Color Center Laser Spectroscopy

The development of cw color center lasers [1] has inevitably led to their application to spectroscopy. The commercial availability of a color center laser provides ready access to this technology to any laboratory. In this paper, we wish to examine the prospects of color center lasers as tunable sources for high sensitivity infrared absorption spectroscopy, describe the development of a computer-controlled color center laser spectrometer based upon the commercial Burleigh FCL-20 laser, and report on several spectroscopic investigations using the computer-controlled color center laser.