ELECTRIC FIELD INDUCED SPECTRA OF HYDROGEN, DEUTERIUM, AND NITROGEN

$^{1}$P. A. Jannson, R. H. Hunt, and E. K. Plyler, J. Opt. Soc. Am. 60, 596 (1970).Author Institution: UTMSL, Molecular Spectroscopy Laboratory, Department of Physics and Astronomy, The University of TennesseeThe shifts of the Q-Branch fundamental, electric field induced absorption lines of hydrogen and deuterium have been measured on the new five-meter Littrow spectrometer. The shifts with density are clearly in the linear region and the zero pressure frequencies are calculated. Selected lines in hydrogen have been deconvoluted using the basic method of $Jannson^{1}$ which has been modified. The process of deconvoluting lines has been highly automated using digitally recorded data on magnetic tape and Fortran coded programs. The results of a search for the field induced spectrum of nitrogen will be presented. The Q branch was observed but the absorption with the achievable field was insufficient to enable us to make quantitative measurements

VERY HIGH ELECTRIC FIELD INDUCED PURE ROTATION SPECTRUM OF HYDROGEN.

Author Institution: Department of Physics, University of Tennessee; Sandia Corporation Alburquerque, New Mexico, 87103This research was supported by NASA Grants NsG 539 and NGL 43-001-006. Present address of P. J. Brannon: Sandia Corporation, Albuquerque, New Mexico.A new Stark cell capable of producing higher electric field intensities than had been before achieved was built and used to examine the pure rotation infrared spectrum of the hydrogen molecule. The higher field intensities were achieved by the elimination of plastic spacers traditionally used in previous Stark cells between the parallell plate electrodes. Operating field intensities of 200,000 volts/cm are easily obtained in compressed hydrogen at a pressure of 400 p.s.i., compared to a previous maximum of 135,000 volts/cm at 550 p.s.i. in a similar cell. Peak field intensity in the new cell just before breakdown is 240,000 volts/cm in hydrogen at 400 p.s.i. The fundamental vibration-rotation spectrum and the pure rotation spectrum of hydrogen were observed using the new cell. The pure rotation spectrum was measured since it has not been observed before using the electric field induced method. The wave numbers of the $S_{0}(1), S_{0}(2)$ and $S_{0}(3)$ transitions were measured to be $587.079 cm^{-1}, 814.523 cm^{-1}, 1034.765 cm^{-1}$ respectively. These values were used to calculate the molecular constants of hydrogen. The calculated value for $B_{o}$ was 59.332, for $D_{o}: 0.0450$ and for $H_{o}: 3.1 \times 10^{-5}$, in cm$^{-1}$

DETERMINATION OF η\eta FOR THE SPECTRAL LINE R (4) OF HYDROGEN FLUORIDE∗FLUORIDE^{*}

$^{*}$Supported by the Air FORCE Cambridge Research Laboratories. $^{\dag}$Supported by the U. S. Naval Postgraduate School.Author Institution: The University of Tennessee“The line shape of pressure-broadened spectral lines can be represented by the modified Lorentz expression $\alpha = \alpha_{o}(\Delta \nu)^{2}[|\nu - \nu_{o}|^\eta + (\Delta \nu)^{2}]^{-1}$. An investigation of the value of $\eta$ for the R(4) spectral line of the fundamental band of HF has been made to determine the variation of as a function of distance from line center. The range $\eta$ was found to be $\eta = 2.00$ for $|\nu - \nu_{0}| 3 cm^{-1}$, and n varies linearly from 2.00 to $1.82 \pm .03$ for $2 cm^{-1} < | \nu - \nu_{o}| < 3 cm^{-1}$.

TESTS OF DECONVOLUTION METHOD

Author Institution: Molecular Spectroscopy Laboratory, Department of Physics and Astronomy, The University of Tennessee KnoxvilleTests of the effects of iterative deconvolution on restoration of line shapes of isolated lines and on line positions in dense clusters have been carried out to determine limiting conditions on response function width, signal to noise ratio, etc

LINE STRENGTH MEASUREMENTS OF NO IN THE 5μm5\mu m REGION

$^{1}$J.-Y. Mandin, C, Amiot., G, Guelachvili, Amm, Phys, Fr., 5, 91-112 (1980).Line strengths have been determined for a number of P and R branch lines of the 1-0 band of NO. Data was obtained using the 5-meter Littrow spectrometer operating under computer control, The reproducibility of successive scans of a line with the stepping motor driven tangent arm-system permits averaging of a number of successive scans of each line to improve the precision of the results. Because the A-doubling is not fully resolved, explicit treatment of the A- doubling in the equivalent width calculations is necessary. Details of the calculations as well as $NO_{1}$ line strengths are presented. Results will be compared with recently published $strengths.^{1}

DEVELOPMENT OF A NEAR INFRARED-VISIBLE SPECTROPHOTOMETER AT UTMSL

Author Institution: Molecular Spectroscopy Laboratory, Department of Physics and Astronomy University of Tennessee, KnoxvilleA high resolution spectrometer has been designed to operate in the wavelength region spanning the near infrared through the visible. The monochromator configuration is a 1 1/4 meter Ebert-Fastie. The grating is a Bausch and Lomb $5 \times 10$ inch, 316 groove per millimeter echelle driven by a programmable stepping drive. A Perkin Elmer Model 112 spectrometer equipped with a $CaF_{2}$ prism has been modified to act as a predisperser. The sample section follows the monochromator so that only the highly dispersed light excites the sample gas. An interesting feature of the sampling section is the method of double beaming. A beam flipping mirror shifts the sample beam through two paths to a single detector. The signal from the detector [lead sulphide or photomultiplier] is amplified and digitized by an $A/D$ converter and then routed by a PDP-11 computer system to a storage buffer. Design features and performance will be discussed

DESIGN AND OPERATION OF THE UTMSL DATA ACQUISITION, INSTRUMENTAL CONTROL AND INTERACTIVE ANALYSIS SYSTEM

Author Institution: Molecular Spectroscopy Laboratory, Department of Physics and Astronomy University of Tennessee, KnoxvilleAn in-house custom designed data acquisition, instrument control and interactive analysis system has been integrated into the molecular spectroscopy laboratory. The system provides data acquisition and instrumental control for both high resolution spectrometers in the laboratory. Real time digital filtering as well as programmed control of the spectrometers has increased data acquisition rates. Thus the state of the art lifetime of the instruments has effectively been extended by increasing the quantity of data which may be obtained during actual instrumental state of the art lifetime. In addition, the interactive measurement and analysis capabilities are designed to reduce the difficulty and time lapse normally encountered in the labor intensive phase of measurement and analysis of very high resolution spectral data. The data acquisition and control system spools data from a maximum of four infrared detectors and controls up to 48 instruments functions. Eight additional analog sense lines (A/D) and eight analog control lines (D/A) are provided. These lines are used for prism predisperser control, plotting, etc. Real time data display is available on a closed circuit television system; interactive measurement and preliminary analysis capability is provided by a light pen interactive graphic display. Bulk storage is available on magnetic tape and disc systems and spooling of jobs for the local batch processor facility is accomplished using an industry compatible tape system