Rolf Engleman
Los Alamos National Laboratory
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Featured researches published by Rolf Engleman.
Journal of Molecular Spectroscopy | 1971
Rolf Engleman; P.E. Rouse
Abstract The ultraviolet β and γ band systems of nitric oxide were photographed at high resolution following the flash photolysis of nitrosyl chloride in excess argon. Between 2700 and 3100 A, 17 bands of the NO γ system and 11 bands of the NO β system were found and analyzed. Molecular constants were derived for v ″ = 0, 1, ⋯, 16 of the X 2 Π ground state, and v ′ = 0, 1, ⋯, 5 for both the A 2 Σ and B 2 Π excited states.
Journal of Chemical Physics | 1979
E. F. Zalewski; Richard A. Keller; Rolf Engleman
Irradiation of a neon‐supported, uranium hollow cathode discharge at wavelengths between 572 and 672 nm corresponding to optical transitions in neon or uranium causes significant changes in the impedance of the discharge. The behavior of these transitions can be separated into two general classes. (I) For transitions originating in the 1s levels of neon the impedance change is either negative or positive, depending upon the particular state, and the magnitude is proportional to the probability of depletion of these levels by optical pumping. (II) For other neon and all uranium transitions these impedance changes are negative and are proportional to the probability for absorption of laser radiation. Spatial variation of the impedance changes demonstrate the importance of collisions of the metastables with the cathode wall in maintaining the discharge.
Journal of the Optical Society of America | 1979
Richard A. Keller; Rolf Engleman; E. F. Zalewski
Laser induced impedance changes in a hollow cathode discharge containing sputtered uranium atoms were used for standard spectroscopic measurements, the determination of oscillator strengths, the measurement of the electron temperature of the discharge, isotope ratio analysis, and obtaining information about the sputtering process. Concentrations of uranium atoms as small as 108/cc could be detected.
Journal of Molecular Spectroscopy | 1974
Rolf Engleman
Abstract The low J rotational lines of the (v′=v″; v″=0, 1, …, 7) and (v′=v″+1; v″=0, 1, …, 6) bands of the B2Σ+ → X2Σ+ transition in the CN free radical have been measured from absorption spectra obtained during the flash photolysis of low pressure BrCN in excess argon. Rotational analysis has yielded accurate molecular constants for these states. A perturbation between the B2Σ+ (v′ = 5) and A 2 Π 1 2 (v′ = 17) states has been found and analyzed.
Astrophysical Journal Supplement Series | 1994
Mark C. Abrams; Sumner P. Davis; M. L. P. Rao; Rolf Engleman; James W. Brault
The infrared spectrum of the hydroxyl radical OH, between 1850 and 9000/cm has been measured with a Fourier transform spectrometer. The source, a hydrogen-ozone diffusion flame, was designed to study the excitation of rotation-vibration levels of the OH Meinel bands under conditions similar to those in the upper atmosphere which produce the nighttime OH airglow emission. Twenty-three bands were observed: nine bands in the Delta upsilon = 1 sequence, nine bands in the Delta upsilon = 2 sequence, and five bands in the Delta upsilon = 3 sequence. A global nonlinear least-squares fit of 1696 lines yielded molecular parameters with a standard deviation of 0.003/cm. Term values are computed, and transition frequencies in the Delta upsilon = 3, 4, 5, 6 sequences in the near-infrared are predicted.
Spectrochimica Acta Part B: Atomic Spectroscopy | 1984
Lynda M. Faires; Byron A. Palmer; Rolf Engleman; Thomas M. Niemczyk
Abstract A vertical profile of iron I excitation temperature in the inductively coupled plasma was determined using spectroscopic techniques based on the Einstein-Boltzmann expression for spectral line intensity and the powerful information gathering ability of a high resolution Fourier transform spectrometer. Calculated temperature values were found to be critically dependent on the oscillator strength values chosen from the literature; however, a qualitative picture of the vertical excitation temperature gradient in the plasma was well-defined and was found to reach a maximum value in the normal analytical zone of the plasma. Excitation temperatures for iron I, nickel I, cobalt I, and vanadium I and II in the normal analytical zone of the plasma were also determined by the same method.
Journal of Quantitative Spectroscopy & Radiative Transfer | 1969
Rolf Engleman
Abstract The collision broadening cross sections of the OH (0, 0) (A → X) ultraviolet transition have been measured for 14 broadening gases at 293°K and for water vapor at 378°K. They were obtained by applying corrections for Doppler and instrumental broadening to direct width measurements of OH absorption lines in high resolution spectra. The OH was generated by flash photolysis of H2O2 or H2O in an excess of broadening gas. The assumption that the cross section is independent of the OH rotational quantum number J appears valid for all these gases except water, for which it was necessary to assume that the cross section is a decreasing function of J. The collision widths at 293°K and 580 torr range from a low of 0·04 cm-1 for helium to a high of 0·16 cm-1 for hydrogen. For water vapor at 378°K and 546 torr, the collision width varies from about 0·3 cm-1 for J = 1 2 ; to about 0·06 cm-1 for J = 7 1 2 ;. The collision widths, when extrapolated to flame temperatures, appear to agree with earlier measurements as well as can be expected. The cross sections obtained are generally larger than those derived from transport property measurements, but all are within a factor of two of the latter values.
Journal of Quantitative Spectroscopy & Radiative Transfer | 1973
P.E. Rouse; Rolf Engleman
Abstract Quantitative high-resolution spectroscopy was applied to the (0,0) and (1,0) U.V. absorption bands of OH and OD. Known concentrations of OH and OD were prepared in a high-temperature furnace containing a 2:1 mixture of water vapor and oxygen. Band oscillator strengths at 1425 K for the OH (0,0), OH(1,0), OD (0,0) and OD (1,0) bands were 9.6 × 10-4, 2.4 × 10-4, 9.5 × 10-4 and 2.6 × 10-4 with a statistical and systematic uncertainty of about 20 per cent. The use of the OH or OD rotational intensity distribution with vibration-rotation correction factors to determine gas temperature was verified. The collision width of OH or OD lines in the furnace at a total pressure of 580 torr is about 0.14 cm-1 at low J″ and appears to decrease at higher J″.
Applied Optics | 1980
Richard A. Keller; Rolf Engleman; Byron A. Palmer
The accuracy of laser wavelength calibration was demonstrated using a uranium hollow cathode discharge tube. (AIP)
Journal of the Optical Society of America | 1983
Rolf Engleman; Byron A. Palmer; S. J. Davis
We have made direct absorption measurements of the transition probability and collision broadening of the 1.3-μm 2P1/2 → 2P3/2 transition of atomic iodine. Atomic iodine was generated in heated iodine vapor, and the spectrum was obtained with a Fourier-transform spectrometer. A transition probability was measured that corresponds to a 2P1/2 radiative lifetime of 125 msec. Broadening coefficients of 1.4, 1.7, 3.1, and 1.3 MHz/Torr at 1000 K were found for argon, oxygen, molecular iodine, and atomic iodine, respectively. The intensity of the (2, 4) forbidden electric-quadrupole line was measured and yielded the ratio of electric-quadrupole to magnetic-dipole transition probability of 2.7 × 10−3. Molecular absorption spectra of IO and SiI were seen in high-temperature spectra of a quartz cell containing an I2/O2 mixture.