A self-consistent field for the H2 molecule

We investigate the simple harmonic oscillator in a 1D box, and the 2D isotropic harmonic oscillator problem in a circular cavity with perfectly reflecting boundary conditions. The energy spectrum has been calculated as a function of the self-adjoint extension parameter. For sufficiently negative values of the self-adjoint extension parameter, there are bound states localized at the wall of the box or the cavity that resonate with the standard bound states of the simple harmonic oscillator or the isotropic oscillator. A free particle in a circular cavity has been studied for the sake of comparison. This work represents an application of the recent generalization of the Heisenberg uncertainty relation related to the theory of self-adjoint extensions in a finite volume.     

Far-infrared absorption in H2 and H2-HE mixtures

Collision-induced absorption in the translation-rotation band of H₂ and H₂-He mixtures has been measured from 20 to 900 cm^-1 at 77.4, 195 and 292 K. To establish the accuracy of the results, various sources of error are investigated. The zeroth and first spectral moments are evaluated from experiment and theory for H₂ at the various temperatures. To obtain theoretical moments consistent with the experimental values, the quantum pair-distribution function must be used. The major portion of the experimental moments can be accounted for by quadrupole-induced dipoles in H₂ pairs. The remaining portion is attributable to an anistropic overlap interaction, although its magnitude depends on the value of the molecular parameters required to calculate the quadrupole contribution.     

Tea CO2 laser beam absorption in polyethylene

The absorption coefficient of polyethylene sheets has been measured for two wavelengths (0.6328 μm, He-Ne laser; 10.6 μm, CO₂ laser). For TEA CO₂ laser power densities up to 10⁴ W cm⁻², the absorption coefficient was found to be 35.36 cm⁻¹. The measured absorption coefficient shows that polyethylene sheets are good and simple attenuators for CO₂ laser radiation.     

Search for anomalous scattering of keV neutrons from H2O-D2O mixtures

We measured the neutron scattering intensities from pure liquid H2O relative to that of pure D2O and also relative to H2O-D2O mixtures, at room temperature. This study is relevant to the problem of quantum entanglement. The neutrons were generated from an electron Linac and the final energy of the scattered neutrons was fixed at 24.3 keV using a 20 cm thick pure iron filter. The scattering intensity ratios were found to agree with expected values deduced from the tabulated total cross sections within an accuracy of 3%. Thus no anomaly was observed.     

CO2-laser-induced multiphoton absorption of CF2Cl2

Energy absorption by CF₂Cl₂ from an intense TEA CO₂ laser pulse is measured as a function of the pressure of CF₂Cl₂ and the pressure of Ar bath gas for different laser energy fluences. The fraction of the molecules excited by the laser field and the average energy of the molecular ensemble are determined by a simple experimental method.     

Broadening of absorption lines of the v2 band of the H2S molecule by the pressure of atmospheric gases

The broadening coefficients γ of absorption lines of the v₂ band of H₂S molecules due to the pressure of molecular gases H₂S (self-broadening), H₂O, N₂, O₂, H₂, D₂, and CO₂ have been calculated by the semiclassical methods. A satisfactory agreement with the experimental data available for some lines has been achieved. In all cases, the parameters of an analytical model allowing the reconstruction of the calculated and experimental values of γ have been determined. For the case of line self-broadening, the calculation has been performed for several temperatures in the range 296 K ≤ T ≤ 1300 K and the parameters determining the temperature dependence of γ have been obtained.     

Excitation transfer between excited electronic states of the H2 molecule due to interaction with a CO2 Laser beam

A spectroscopic study of the band systemsG ¹ Σ _g →B ¹ Σ _u andI ¹ Π _g →B ¹ Σ _u of H₂ emitted by a glow discharge in H₂ gas showed that the populations of theG ¹ Σ _g (v, J) states decrease for the benefit of theI ¹ Π _u (v′, J′) states when the discharge is irradiated by a powerful CO₂ Laser beam (power density 70 kW/cm²). The effect is interpreted as an absorption process in which two Laser photons intervene according to the transition scheme:G ¹ Σ _g →B″¹ Σ _u →I ¹ Π _g. A change of the populations of excited electronic states should lead to a change of the populations of excited atomic states as well.     

Electronic structure of the H+2 molecule

Main results of investigations aimed at a construction of the classical model of the H⁺₂ molecule are presented. The form of the orbit of the electron, binding two nuclei of the H⁺₂ molecule together has been deciphered. Theoretical value of the structural parameter, which is the distance between nuclei times the binding energy of the electron, was found to be equal with a high accuracy to that experimentally measured.     

Orbits in the H(2)O molecule

We study the forms of the orbits in a symmetric configuration of a realistic model of the H(2)O molecule with particular emphasis on the periodic orbits. We use an appropriate Poincare surface of section (PSS) and study the distribution of the orbits on this PSS for various energies. We find both ordered and chaotic orbits. The proportion of ordered orbits is almost 100% for small energies, but decreases abruptly beyond a critical energy. When the energy exceeds the escape energy there are still nonescaping orbits around stable periodic orbits. We study in detail the forms of the various periodic orbits, and their connections, by providing appropriate stability and bifurcation diagrams. (c) 2001 American Institute of Physics.     

CO在MoS2/K2CO3/TiO2上的加H2反应

根据“盐类及氧化物等在高比表面载体上有自发分散倾向”的原理，制备了一种新型的用于由合成气（H2／CO）合成甲醇的催化剂MoS2/K2CO/TiO2(DSA),该催化剂具有较好的耐硫性和对甲醇有较高的选择性，通过对反应条件的教察得出结论：高压、低温、高空速有利于提高醇的选择性。     

红外吸收峰的强度与反常吸收现象

红外光谱测量有时需要在强的背景信号下得到弱的样品吸收峰,如在大量溶剂中测量溶质的红外光谱.理论上,只要某一组分在背景样品和待测样品的含量(分子个数)完全一致,则该组分的光谱信号就不会出现在最终的红外光谱图上.而实际测量时结果并非总如此.本文在测量聚苯乙烯及硬脂酸的“基线”时发现,在样品吸收较强的峰位(吸光度A＞1.0)...     

Two-photon absorption method for the study of collisional relaxation of atoms in a perturber bath

A two-photon absorption study was performed with sodium vapour at about 300°C perturbed by noble gases at densities between 0.5 x 10¹⁹ and 6 x 10¹⁹ atoms/cm³. The collisional relaxation of the 3P_{$\text{3}\text{2}$} and 3P_{$\text{1}\text{2}$} states has been measured for several noble gases. The origin of relaxation is interpreted as the result of a reactive collision leading to an excited molecular state. The recombination rate coefficients of the three-body reaction are calculated and their values are compared to those given by Scheps and Gallagher.     

Shock tube/laser absorption measurement of the rate constant of the reaction: H2O2 + CO2 2OH + CO2

We address the role of the linear mixing rule in the kinetics of the H₂O₂ decomposition system by reporting the rate constant for H₂O₂ + M = 2OH + M (M = Ar and CO₂) in the temperature range of 1087–1234 K at low pressures in a mixture of 20% CO₂ in Argon. The reaction rate constant was inferred from H₂O concentrations monitored by using a laser-absorption spectroscopy-based water diagnostic. To the best of our knowledge, this is the first measurement of the rate constant of this reaction in a mixture to be reported in literature. A significant discrepancy was found between the rate constants derived using the traditional linear mixing rule and the reduced pressure linear mixing rule. This discrepancy can have serious implications on the predictive accuracy of these kinetic models, especially under conditions relevant to the operation of supercritical CO₂ (sCO₂) power cycles that rely on oxy-fuel combustion in a working fluid comprised almost entirely of CO₂.     

Symmetry-resolved absorption spectra of vibrationally excited CO2 molecules

Symmetry-resolved x-ray absorption spectroscopy has been first carried out on high-temperature molecules. From the angle-resolved ion yield spectra of CO2 both at room temperature and at 430 degrees C, symmetry-resolved absorption profiles of the C 1s(-1) 2pi(u) and O 1s(-1) 2pi(u) resonances have been extracted for the vibrational ground state molecules and bending-vibration excited ones. The profiles change dramatically between them, and the Renner-Teller effect becomes more evident for the vibrationally excited molecules. The effects of the multimode vibronic coupling are suggested for the O 1s(-1) 2pi(u) and O 1s(-1) 3s sigma(g) resonances.