Analysis of ν2 of D2S

The infrared spectrum of ν₂ of D₂S was recorded from 740 to 1100 cm^?1 on the University of Denver 50-cm FTIR spectrometer system. We have assigned 655 transitions from D₂³²S and 129 from D₂³⁴S, and have analyzed them using Watson's A-reduced Hamiltonian evaluated in the I^r representation. We used the recently published D₂³²S and D₂³⁴S ground state Hamiltonian constants [C. Camy-Peyret, J. M. Flaud, L. Lechuga-Fossat and J. W. C. Johns, J. Mol. Spectrosc.109, 300–333 (1985)]. Upper state Hamiltonian constants were obtained from a fit of the ν₂ transitions, keeping the ground state constants fixed while varying the upper state constants. The standard deviation of the D₂³²S ν₂ fit is 0.0025 cm^?1. The standard deviation of the D₂³⁴S ν₂ fit is 0.0041 cm^?1.     

D3d distortion in CsUF6

A slight D_3d distortion on the octahedral UF₆^? complex splits the Γ^'₈ and Γ₈ octahedral levels into four doublets. These doublets and other electronic levels of the CsUF₆ ground configuration have been identified according to their vibronic side-bands. In the calculation of the crystal field Hamiltonian, the amount of D_3d distortion on the UF₆^? octahedron is treated as the parameter, Δ. The interactions of the 5f electron of the UF₆^? complex contains five parameters: ξ_5f, B₂⁰, B₄⁰, B₆⁰ and Δ. The calculated energy spectrum and the g-tensor of the ground state show good agreement with the experimental measurements.     

Improved infrared and visible emission spectra of the H3 and D3 molecules

Better-resolved Rydberg-Rydberg emission spectra of the neutral H₃ and D₃ molecules in the infrared and visible regions, with less interference from H₂ and D₂ emission, have been obtained by using a Droege-Engelking type of corona discharge source. Using nl_λ notation, the lower electronic states are 3p₁ in the infrared and 2p₀ in the visible, and the upper electronic states are mixed (3s,3p₀,3d₀,3d₁,3d₂) states. In particular, a line near 16 842 cm⁻¹ in H₃, previously obscured by an H₂ line, reveals a (3s,3d) interaction that is confirmed by other lines. The spectra are analysed including this interaction. However, fits to effective Hamiltonians still have relatively large standard deviations, probably partly due to poor convergence of the rotational expansions and partly due to many small perturbations of the levels by background states.     

Atomic-potential parameters for H2 and D2: quantum corrections in the calculation of second-virial coefficients

First-order quantum corrections were introduced into the computation of the second-virial coefficients of H₂ and D₂. The quantum effects, for the studied two light molecules, are considerable even at the room temperature and become prominent at low temperatures. Atomic potentials, incorporating the quadrupole interactions, were employed in the calculations. Optimum atomic-potential parameters ε_H, σ_H, ε_D and σ_D were obtained from the nonlinear least-squares fit of the experimental second-virial coefficients. The fitted virial coefficients cover the temperature ranges of 173-423 and 153- for H₂ and D₂, respectively.     

Collision-induced first overtone band of D2 in binary mixtures D2-X where X is Ar, Kr, and Xe

Enhancement spectra of the collision-induced absorption in the first overtone region 5500-6750 cm⁻¹ of D₂ in the D₂-Ar, D₂-Kr, and D₂-Xe binary mixtures were studied at 298 K for base densities of D₂ in the range 55-251 amagat and for partial densities of Ar, Kr, and Xe in the range 46-384 amagat. The observed spectra consist of the following quadrupolar transitions: O₂(3), O₂(2), Q₂ (J), J = 1-5 and S₂ (J), J = 0-5 of D₂. Binary and ternary absorption coefficients were determined from the integrated absorption coefficients of the band. Profile analyses of the spectra were carried out using the Birnbaum-Cohen (BC) lineshape function and characteristic lineshape parameters were determined from the analyses.     

十一甲川和五甲川染料的吸收和弛豫时间

本文报道了用于掺钕激光材料锁模的中国快速可饱和吸收染料D₁(十一甲川)和D₂(五甲川)的吸收和弛豫时间的测量结果。 关键词：     

Photoelectron angular distributions from H2 and D2

The photoelectron asymmetry parameters of H₂ and D₂ have been measured using synchrotron radiation over the photon energy range 19–27 eV. The results are compared with previous measurements and several theoretical calculations. A few of the theoretical calculations are in good agreement with experiment, but most of them predict asymmetries which are too large. Essentially identical β values were measured for H₂ and D₂. This result is discussed in terms of differences which could arise due to vibrational and rotational structure.     

Lyman transitions of high rovibrationally excited H2, HD and D2 molecules

Energies and probabilities of Lyman transitions of high rovibrationally excited H₂, HD and D₂ molecules have been measured and compared with calculations. The experimental results are obtained from laser-induced fluorescence spectra that have been recorded in the spectral range from 60 500 to 83 500 cm⁻¹, covering 2/3 of the hydrogen Lyman band system. The necessary vacuum-UV radiation is produced by stimulated anti-Stokes Raman scattering, providing a widely tunable radiation source with narrow spectral bandwidth to resolve single Lyman transitions. The highest internal energies of detected hydrogen isotopologues are close to the dissociation limit. This extends the available data base of Lyman transitions from and to higher rotational states (J > 10) of HD and D₂.     

The fundamental band ν2 of D2CO

The ν₂ band of D₂¹³CO in the region of 1570-1760 cm⁻¹ has been analyzed with high accuracy. The limits of the quantum numbers J and K_a are 50 and 16, respectively. The number of the assigned transitions is 3858. A local anharmonic resonance ν₂/2ν₄ at K_a =  8-12 was observed. The Watson’s A-reduced Hamiltonian and anharmonic resonance term were fitted to the observed transitions. The fit resulted in the band center and rotational parameters of the ν₂ band as well as the effective parameters for the 2ν₄ band and anharmonic resonance parameter. The rms deviation of the transitions in the ν₂ band was 0.000364 cm⁻¹.     

Penning ionization electron spectroscopy of H2O,D2O,H2S and SO2

Electron energy peak shifts and peak shapes were determined in the ionization of H₂O, D₂O, H₂S and SO₂ by Ne(³P₂) and He(2¹S, 2³S) metastable atoms. The shifts are large, especially in ionization of H₂O and D₂O into the ionic ground state and are probably mostly due to chemical interaction during the collision.In a previous paper the electron energy distribution curves for ionization of CO, HCl, HBr, N₂O, NO₂, CO₂, COS and CS₂ by helium, neon and argon metastables and the characteristics of this ionization were described¹. In this paper the series of triatomic molecules was extended to the molecules H₂O, D₂O, H₂S and SO₂. Because all these molecules have considerable dipole moments it could be expected that the peak shifts might be enhanced as compared with other triatomic molecules.     

Analysis of the CIA spectra of the first overtone band of D2 in D2-N2

Enhancement spectra of the collision-induced absorption (CIA) in the first overtone region 5000-7000 cm⁻¹ of D₂ in D₂-N₂ were studied at 298 K for a base density of D₂ of 73 amagat and for partial densities of N₂ in the range 150-370 amagat. The observed spectra were modeled with a total of 1176 components of double vibrational transitions. Binary and ternary absorption coefficients were determined from the integrated absorption of the band. Profile analysis of the spectra was carried out using the Birnbaum-Cohen line-shape function for the individual components of the band, and characteristic line-shape parameters were determined from the analysis. Good agreement was obtained between the experimental and calculated spectral profiles.     

Collision induced absorption spectra of the fundamental band of D2 in binary mixtures D2-Kr at 298 K

The enhancement spectrum of the collision induced absorption of D₂ in its fundamental band region 2600-4000 cm⁻¹ in binary mixtures D₂-Kr was studied at 298 K for base densities of D₂ in the range 9-20 amagat and for partial densities of Kr in the range 7-120 amagat. The binary absorption coefficient of the band has been determined from the measured integrated absorption coefficient and found to be 3.9 × 10⁻³ cm⁻² amagat⁻². An analysis of the experimental spectrum was carried out by assuming appropriate line-shape functions and the half-width parameters δ₁, δ₂, δ_d and δ_c of the long range quadrupole, and of the short range overlap induced transitions have been determined. Good agreement was obtained between the recorded spectrum of the fundamental band and the synthetic profile.     

High temperature thermodynamics of H2 and D2 in titanium,and in dilute titanium oxygen solid solutions

The Tian Calvet microcalorimetric method has been improved in order to determine Δ$\text{H}$_H(D), the partial molar enthalpy of mixing of hydrogen (deuterium) in the Ti-H₂(D₂) solid systems for compositions 0 < (H/Ti) < 1.85, at 713 K and in the α TiO_y + H₂ solid solutions (y = (O/Ti)) at 745 K. The combined calorimetric and equilibrium method allows a precise evaluation of the partial molar entropies. The results of this study differ substantially from earlier published data.     

Microwave spectra of D217O and D218O

Forty lines of the microwave spectra of D₂¹⁷O and D₂¹⁸O have been measured in the region from 8 to 400 GHz and analyzed according to Watson's centrifugal distortion theory. Comparison of the results obtained for D₂¹⁶O, D₂¹⁷O, and D₂¹⁸O demonstrates their internal consistency. The transferability of the parameters according to the isotopic substitution rules is evidence for the validity of the model chosen for the study of the ground state of heavy water.The effective rotational constants deduced from the observed spectra are very close to the values calculated using Oka's second order theory. The values obtained in MHz are:

$\text{A = 456766.9,}\text{B = 218041.0,}\text{C = 144701.5}\text{(D}{}_2{}^{17}\text{O;)}$

$\text{A = 451891.9,}\text{B = 218045.2,}\text{C = 144201.7}\text{(D}{}_2{}^{18}\text{O;).}$

The hyperfine structure of the D₂¹⁷O lines has been analyzed using as a reference the corresponding quadrupole coupling tensor of HD¹⁷O with the appropriate rotation. The values of χ_gg in MHz used for the analysis are:

$\text{x}{}_{\mathrm{\chi \chi }}\text{= - 1.2104,}\text{x}{}_{\mathrm{yy}}\text{= 10.1068,}\text{x}{}_{\mathrm{zz}}\text{= - 8.8964.}$

     

Wing profile measurements of the Na-doublet lines in C2H2/O2/N2, H2/O2/N2 and H2/O2/Ar frames at 1 atm

Fluorescence-excitation (wing) profiles of the Na-D doublet lines were measured over a wavelength range extending from 0.3 to 200 Å from the line center for the red D₁ and blue D₂ wings and from 0.3 to 3 Å for the red D₂ and the blue D₁ wings, respectively. The line profiles were determined with the aid of a tunable CW dye-laser as a background source by measuring the total fluorescence intensity observed on detuning the laser wavelength. The flames were premixed, laminar, shielded flames at 1 atm, with temperatures ranging from 1860 to 2270 K; N₂ and Ar served as diluent gases. The line core and near-wing profiles (i.e. the region covering 0.3<Δλ<7 Å for the outer wings and 0.3<Δλ<3 Å for the inner ones) in all of the flames studied appeared to have the same frequency dependence, regardless of the nature and concentrations of the gases used. The blue D₂-line profile followed an unexpected (-2.2) law, while the other three profiles obeyed the theoretically expected (-2) law (the dispersion profile function). The line profile in the Δλ range between the impact and quasistatic regions was found to depend on the main perturbers involved. We found that the far blue D₂- and red D₁-wings in the Ar-diluted H₂/O₂ flame obeyed the (-$\text{5}\text{4}$) and (-$\text{3}\text{2}$) laws, respectively, as predicted by the quasi-static theory for the Lennard-Jones interaction. For the N₂-diluted C₂H₂/O₂ and H₂/O₂ flames, we did not find these wing dependences in the Δλ range investigated.     

Accurate rest frequencies of submillimeter-wave lines of H2D and D2H

We re-examined the submillimeter-wave transition frequencies of H₂D⁺ (J = 1₁₀ − 1₁₁ at 372.4 GHz) and D₂H⁺ (J = 1₁₀ − 1₀₁ at 691.7 GHz) to resolve suggested slight difference in velocity (v_LSR) of these species detected in the cold pre-stellar core 16293E recently. Both H₂D⁺ and D₂H⁺ were generated in a magnetically confined extended-negative glow discharge of a gaseous mixture of H₂/D₂/Ar. A combination of small improvements in various aspects of the measurements such as double modulation technique combined with a conventional frequency modulation and magnetic field modulation and more efficient signal accumulation method allowed us to improve signal-to-noise ratio, and thus to determine the transition frequencies more accurately. Both transition frequencies for the H₂D⁺ and D₂H⁺ lines have been thus determined to be 372421.385(10) and 691660.483(20) MHz, respectively. These precise rest frequencies suggest that the v_LSR of H₂D⁺ and D₂H⁺ in the pre-stellar core 16293E are indeed different as indicated in a recent astronomical observation. In addition, in this investigation, another transition of H₂D⁺ which falls in this frequency region, J = 3₂₁ − 3₂₂ transition, has been observed at 646430.293(50) MHz. As H₂D⁺ is a lightest asymmetric-top molecule and it is difficult to predict the rotational transition frequencies by using the effective asymmetric rotor Hamiltonian, any new observation of the rotational lines will be useful to improve the molecular parameters. The molecular constants for the ground state have been obtained for H₂D⁺ and D₂H⁺ by fitting these new measured frequencies together with the combination differences.     

Mass spectroscopy of HCN-laser plasmas with H2 and D2

Mass spectroscopic studies reveal the role of H₂ in HCN-laser plasma. This is confirmed by laser experiments with different gas mixtures containing H₂ and D₂.     

Interaction of PH3 coadsorbed with H2, D2, O2 and H2O on Rh(100)

The coadsorption of PH₃ with H₂, D₂, O₂ and H₂O on Rh(100) has been studied using temperature programmed desorption (TPD), Auger electron spectroscopy (AES) and low energy electron diffraction (LEED). The adsorption and molecular desorption of PH₃ is not affected by preadsorbed H₂, D₂ and O₂. Preadsorbed PH₃ blocks H₂ desorption sites while postdosed PH₃ displaces H₂ (D₂₁) from the Rh(100). When D₂ and PH₃ are coadsorbed, no D appears in desorbed phosphine. Preadsorbed O₂ reduces the amount of H₂ desorption (from PH₃ decomposition) and increases the H₂ desorption temperature. There is also some reaction between O(a) and H(a) to form water. Preexposure to H₂O decreases the extent of PH₃ adsorption and of PH₃ decomposition.     

The Raman spectra and cross-sections of the ν2 band of H2O, D2O, and HDO

We report the experimental Raman spectra of the ν₂ band of H₂O, D₂O, and HDO in the vapor phase at room temperature. A complete interpretation of the Raman intensities is carried out employing the variational rovibrational wavefunctions obtained from a Hamiltonian in Radau coordinates and an ab initio polarizability surface at 514.5 nm. We show the importance of the rotation-vibration coupling to obtain the correct line intensities. Several tables with the assignments of the individual rotational-vibrational transitions and their Raman scattering strengths are reported. From these tables, the ν₂ Raman spectra can be simulated up to 2000 K for H₂O, and up to 300 K for D₂O and HDO.