Spin-orbit and core-polarization effects in potassium
Potassium photoionization cross section, including spin-orbit interaction, orientation of photoejected electrons and dipole transition moment correction due to core polarization
Dalgarno, A.↗
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Electron-impact excitation of nitric oxide
The absolute cross sections for the excitation of the NO(+) bands, two nitric oxide beta' bands, and several atomic nitrogen multiplets in the vacuum ultraviolet by electron impact on NO were measured over an energy range extending from threshold to 3000 eV. The variation of the dipole transition moment for the NO(+) band system was also determined.
Stone, E. J.↗
Electron-impact excitation of nitric oxide.
The absolute cross sections for the excitation of the nitrosyl cation Baer-Miescher bands, two nitric oxide bands, and several atomic nitrogen multiplets in the vacuum UV by electron impact on NO have been measured over an energy range extending from threshold to 300 eV. The variation of the dipole transition moment for the nitrosyl cation band system was also determined.
Stone, E. J.↗
Photoabsorption by ground-state alkali-metal atoms.
Principal-series oscillator strengths and ground-state photoionization cross sections are computed for sodium, potassium, rubidium, and cesium. The degree of polarization of the photoelectrons is also predicted for each atom. The core-polarization correction to the dipole transition moment is included in all of the calculations, and the spin-orbit perturbation of valence-p-electron orbitals is included in the calculations of the Rb and Cs oscillator strengths and of all the photoionization cross sections. The results are compared with recent measurements.
Weisheit, J. C.↗
Molecules of significance in planetary aeronomy
This monograph is basically devoted to spectroscopic information of the molecules of planetary interest. Only those molecules have been dealt with which have been confirmed spectroscopically to be present in the atmosphere of major planets of our solar system and play an important role in the aeronomy of the respective planets. An introduction giving the general conditions of planets and their atmospheres including the gaseous molecules is given. Some typical planetary spectra is presented and supported with a discussion on some basic concepts of optical absorption and molecular parameters that are important to the study of planetary atmospheres. Quantities like dipole moments, transition probabilities, Einstein coefficients and line strengths, radiative life times, absorption cross sections, oscillator strengths, line widths and profiles, equivalent widths, growth curves, bond strengths, electronic transition moments, Franck-Condon factors and r-centroids, etc., are discussed. Spectroscopic information and relevant data of 6 diatomic (HF, HCL, CO, H2, O2, N2) and 6 polyatomic (CO2, N2), O3, HeO, NH3, CH4) molecules are presented.
Mohan, H.↗
Thermophysical aspects of re-entry flows
The present conference discusses low density aerothermodynamics, the drag of bodies in rarefied hypersonic flow, transitional hypervelocity aerodynamic simulation and scaling, high temperature kinetics and transport properties, electron-nitrogen molecule collisions in high temperature nonequilibrium air, theoretical studies of dissociative recombination, the transport properties of some atom/ion interactions in air, and the interaction energies, dipole transition moments, and transport cross sections of N(+)-N and O(+)-O. Also discussed are the results of studies of potential fluid mechanisms for enhanced stagnation heating, vortex-induced leeward heating on a biconic at Mach 6 and 10, the effects of surface discontinuities on convective heat transfer in hypersonic flow, computational convergence in chemical reacting flows, and three-dimensional viscous shock layer applications for the Space Shuttle Orbiter.
Moss, J. N.↗
Rovibrational intensities for the Delta V = 1 bands of the X 3Sigma(-) NH radical - Experiment and theory
The vibrational transition dipole moment for the highly reactive radical species NH in its ground electronic state is obtained via the Herman-Wallis effect manifest in emission spectra produced in a plasma reactor. The results of these experiments on the five lowest Delta V = 1 bands are in good agreement with high quality ab initio calculations of the electric dipole moment function.
Chackerian, C., Jr.↗
Transition probabilities and Franck-Condon factors for the second negative band system of O2(+)
Transition probabilities for the second negative band system of O2(+) are computed using the dipole transition moment presented by Wetmore et al. (1984). Vibrational levels v double prime = 0 - 54 of the X2Pi(g) ground state and v prime = - 33 of the excited A2Pi(u) state are included. Franck-Condon factors for ionization-excitation of O2 to O2(+) are also presented.
Fox, J. L.↗
Growth of thin films of organic nonlinear optical materials by vapor growth processes - An overview and examination of shortfalls
Research on the growth of second- and third-order nonlinear optical (NLO) organic thin film by vapor deposition is reviewed. Particular attention is given to the experimental methods for growing thin films of p-chlorophenylurea, diacetylenes, and phthalocyanines; characteristics of the resulting films; and approaches for advancing thin film technology. It is concluded that the growth of NLO thin films by vapor processes is a promising method for the fabrication of planar waveguides for nonlinear optical devices. Two innovative approaches are proposed including a method of controlling the input beam frequency to maximize nonlinear effects in thin films and single crystals, and the alternate approach to the molecular design of organic NLO materials by increasing the transition dipole moment between ground and excited states of the molecule.
Frazier, D. O.↗
Absolute Rovibrational Intensities of C-12O2-16 Absorption Bands in the 3090-3850/ CM Spectral Region
A multispectrum nonlinear least-squares fitting technique has been used to determine the absolute intensities for approximately 1500 spectral lines in 36 vibration - rotation bands Of C-12O2-16 between 3090 and 3850/ cm. A total of six absorption spectra of a high- purity (99.995% minimum) natural sample of carbon dioxide were used in the analysis. The spectral data (0.01/cm resolution) were recorded at room temperature and low pressure (1 to 10 Torr) using the McMath-Pierce Fourier transform spectrometer of the National Solar Observatory (NSO) on Kitt Peak. The absorption path lengths for these spectra varied between 24.86 and 385.76 m. The first experimental determination of the intensity of the theoretically predicted 2(nu)(sub 2, sup 2) + nu(sub 3) "forbidden" band has been made. The measured line intensities obtained for each band have been analyzed to determine the vibrational band intensity, S(sub nu), in /cm/( molecule/sq cm) at 296 K, square of the rotationless transition dipole moment |R|(exp 2) in Debye, as well as the nonrigid rotor coefficients. The results are compared to the values listed in the 1996 HITRAN database which are obtained using the direct numerical diagonalization (DND) technique as well as to other published values where available.
Devi, V. Malathy↗
Molecular Line and Continuum Opacities for Modeling of Extrasolar Giant Planet and Cool Stellar Atmospheres
The molecular line and continuum opacities are investigated in the atmospheres of cool stars and Extrasolar Giant Planets (EGPs). Using a combination of ab inito and experimentally derived potential curves and dipole transition moments, accurate data have been calculated for rovibrationally-resolved oscillator strengths and photodissociation cross sections in the B' (sup 2)Sigma+ (left arrow) X (sup 2)Sigma+ and A (sup 2)Pi (left arrow) X (sup 2)Sigma+ band systems in MgH. We also report our progress on the study of the electronic structure of LiCl and FeH.
Weck, P. F.↗
Molecules in Cool Stars: The A 2 Π − X 2 Σ + and the B 2 Σ + − X 2 Σ + Band Systems of CaCl
Cool red giant stars exhibit absorption bands of calcium monochloride (CaCl) in the optical region. In this work, the bands of CaCl corresponding to the A 2 Π − X 2 Σ + transition with v' ≤ 4 and v'' ≤ 4, and B 2 Σ + − X 2 Σ + transition with v' ≤ 2 and v'' ≤ 2 are rotationally analyzed with PGOPHER, a multipurpose program for simulating and fitting molecular spectra. All bands were analyzed using high-resolution absorption spectra collected at the National Solar Observatory in 1985, calibrated with atomic lines from a high-resolution emission spectrum obtained in a separate hollow cathode experiment. The results are compared with previous laser-induced fluorescence measurements. Overall, the accuracy of spectroscopic constants for the A2Π and B2Σ+ states is improved. Scaled transition dipole moment calculations were used to obtain line strengths. Line lists are provided with Einstein A coefficients and oscillator strengths, which can be used to determine CaCl stellar abundances. Additionally, isotope splittings allowed us to estimate band origins for the 40 Ca 37 Cl isotopologue based on band-head positions.
Léo Lavy↗
Alternating-current-field induced cholesteric- nematic phase transitions
Molecular dipole moments-electric field interaction induction of cholesteric liquid crystal transition to nematic phase
Baessler, H.↗
Double-quantum vibrational energy transfer in the O3-CO and O3-OCS systems
Using the CO2 laser induced fluorescence technique at 298 K for excitation of the P(30) transition in O3 or the P(22) transition in OCS, double-quantum vibrational energy transfer was studied in the O3-CO and O3-OCS binary gas systems. Rapid rates were observed for energy transfer from the CO (nu = 1) to the coupled O3(200), O3(101), and O3(002) levels, as well as for the transfer from the coupled O3(001) and O3(100) levels to the OCS(020) level. Deactivation of OCS by N2, Ar, and OCS was studied and deactivation rate constants were measured. The experimental results are compared with those calculated using the first order perturbation theory of dipole transition-moment interactions (Sharma and Brau, 1969) as modified by Tam (1972). An attempt is made to interpret the obtained results.
Hui, K.-K.↗
Theoretical dipole moments for the first-row transition metal hydrides
Spectroscopic parameters (D sub e, r sub e, mu) are determined for the first-row transition metal hydrides using better than DZP basis sets at the modified coupled pair functional (MCPF) level. Extensive comparisons between MCPF and complete-active space self-consistent field (CASSCF)/MRCI calculations with natural orbital iterations, and studies with more extensive basis sets, show this level of treatment to supply an accurate and cost-effective treatment of these systems. For the transition metal hydrides, the bonding can arise from either the 3d(n)4s(2) or 3d(n + 1)4s(1) atomic asymptotes, or a mixture of both. Since the dipole moment arising from these two bonding mechanisms is very different, the dipole moment is found to be directly related to the 3d population. Thus, the magnitude of the dipole moments provides a sensitive test of the wave function, and gives insight into the nature of the bonding.
Chong, D. P.↗
Electric dipole moment function of the X1 Sigma/+/ state of CO - Vibration-rotation matrix elements for transitions of gas laser and astrophysical interest
The electric dipole moment function of the ground electronic state of carbon monoxide has been determined by combining numerical solutions of the radial Schrodinger equation with absolute intensity data of vibration-rotation bands. The derived dipole moment function is used to calculate matrix elements of interest to stellar astronomy and of importance in the carbon monoxide laser.
Chackerian, C., Jr.↗
Theoretical calculation of low-lying states of NaAr and NaXe
Potential curves as well as dipole moments and linking transition moments are calculated for the ground X 2 Sigma + and low lying excited A 2 Pi, B 2 Sigma +, C 2 Sigma +, (4) 2 Sigma +, (2) 2 Pi and (1) 2 Delta states of NaAr and NaXe. Calculations are performed using a self-consistent field plus configuration-interaction procedure with the core electrons replaced by an ab initio effective core potential. The potential curves obtained are found to be considerably less repulsive than the semiempirical curves of Pascale and Vandeplanque (1974) and to agree well with existing experimental data, although the binding energies of those states having potential minima due to van der Waals interactions are underestimated. Emission bands are also calculated for the X 2 Sigma + - C 2 Sigma + excimer transitions of NaAr and NaXe using the calculated transition moments and potential curves, and shown to agree well with experiment on the short-wavelength side of the maximum.
Laskowski, B. C.↗
The 1.5 - 3.5 Micron Spectroscopy of the Orion H2 Source
A synopsis of current research with near infrared airborne spectroscopy of the Orion molecular hydrogen emission line source is presented. It is suggested that (H2) is the most abundant molecular species in the interstellar medium and is of paramount importance to understand its behavior and distribution in that medium. The H2 has no permanent electric dipole moment which precludes dipole transitions. It is, however, detected in absorption against background starlight by UV electronic transitions and in the IR through electric quadrupole rotation/vibration and pure rotation emission lines. The physical parameters of this region, in the context of their relationships to other members of the complex family of Orion objects, molecular clouds, compact IR sources, H 2 regions, and shock fronts are described.
Davis, D. S.↗