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  • 1
    Electronic Resource
    Electronic Resource
    UV-laser induced photo-oxidation of aqueous benzene solutions: Formation of phenol (1982)
    Springer
    Applied physics 27 (1982), S. 191-194 
    Details
    ISSN: 1432-0649
    Keywords: 35 ; 36 ; 42.60
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract Aqueous solutions of benzene were irradiated by focussed KrF laser light. The formation of phenol together with varying amounts of 1.3-cyclopentadiene-1-carboxaldehyde was shown by uv absorption measurements. A mechanism for this photo-oxidation via benzene radical cations produced by 2-photon ionization of benzene is proposed. Comparative gas phase laser experiments and experiments with unfocussed laser beams were consistent with previous results using incoherent light sources.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00697440
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  • 2
    Electronic Resource
    Electronic Resource
    Isotope separation of32SF6 and12CF3I by a Q-switched CO2 laser (1988)
    Springer
    Applied physics 47 (1988), S. 17-20 
    Details
    ISSN: 1432-0649
    Keywords: 33.80 Wz
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract Pulses with energy of 0.5 to 15 mJ and a repetition rate of 20 kHz from a Q-switched CO2 laser with continuous discharge were employed to dissociate32SF6 and12CF3I at 0.25 mbar. Gas exchange by diffusion is rapid enough to maintain isotopic selectivity. Dissociation yields agree with those measured at slightly raised temperature by a TEA laser. Because photons are cheaper from Q-switched lasers than from TEA lasers, economic consequences can result for isotope separation.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00696203
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  • 3
    Electronic Resource
    Electronic Resource
    CARS investigations of quenching and photochemical reactions in the Na+H2 collision system (1992)
    Springer
    Il nuovo cimento della Società Italiana di Fisica 14 (1992), S. 1065-1073 
    Details
    ISSN: 0392-6737
    Keywords: Stimulated raman scattering and spectra ; CARS ; Photolysis, photodissociation, and photoionization by infrared ; visible ; and ultraviolet radiation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Summary We have carried out parallel studies of the quenching process in Na(3p)+H2 collisions and the possible reactive process in Na(3p)+H2 (v ″=1,2,3) collisions. Rich CARS spectra which were obtained at H2 pressure of 100 mbar and oven temperature of 600 K indicate the presence of vibrationally excited H2 and photochemically produced NaH molecules. Temporal resolution of NaH CARS lines was employed in order to rule out competing collisional processes. We make use of resonantly enhanced CARS methods which enabled us to achieve very high sensitivity for NaH detection.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02455368
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  • 4
    Electronic Resource
    Electronic Resource
    Rotational transitions of N2(a 1Πg) induced by collisions with Ar/He and N2(a 1Πg)–N2(X 1Σ+g) rovibronic energy transfer studied by laser REMPI spectroscopy (1987)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 87 (1987), S. 5251-5255 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: This paper reports the results of two related experiments: (A) The state-to-state rotational transition probabilities of N2(a 1Πg) in collisions with rare gas atoms (Ar or He) were measured by the technique of two-step multiphoton ionization. Results show that the selection rule antisymmetric–symmetric is obeyed. The transition probability drops rapidly with increasing ||ΔJ||. A propensity rule related to the Π+ or Π− symmetry conservation of the electronic wave function during the collision induced rotational transition holds. (B) The cross section for the rovibronic energy transfer between N2(1Πg) and N2(X 1Σ+g) is found to be ∼28 A(ring)2. N2(a 1Πg) product populations show a Boltzmann-like distribution with a rotational temperature suggesting an equipartition of the available energy among the rotational and translational degrees of freedom of the products. A mechanism invoking an intermediate collision complex along with intermolecular electron exchange may explain the results.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.453667
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  • 5
    Electronic Resource
    Electronic Resource
    Two-laser resonance-enhanced photoionization spectrum of benzene (1989)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 90 (1989), S. 3490-3497 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: This paper reports results of an experiment involving two-laser resonance-enhanced photoionization of benzene. The excitation sources were two frequency-doubled dye lasers. The first laser pumped the molecule to a selected vibronic level of its first excited singlet state (1B2u), from where it was ionized by a time-delayed pulse of the second laser. The ion yield depends on the intermediate vibronic state as well as on the wavelength of the ionizing laser. From the structures and intensities of the measured ion spectra we derived vibrational frequencies and molecular parameters of the ground electronic state of the ion to a remarkable accuracy. The contributions of autoionizing Rydberg levels to the ionization cross section can clearly be distinguished from direct ionization. Several resonance peaks were assigned to transitions to vibrational modes within these Rydberg states.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.455859
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  • 6
    Electronic Resource
    Electronic Resource
    Infrared multiphoton dissociation of SF6 at long wavelengths (1989)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 90 (1989), S. 3055-3059 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: The dissociation probability Pd of 32 SF6 was investigated between 908 and 875 cm−1 at room temperature and at 140 K. In the region of the expected Pd maximum of 36SF6 (≈905 cm−1), we found a ten times higher Pd(32) (implying a ten times smaller selectivity for 36S) than expected from extrapolation of shorter wavelength data. The Pd spectrum in this and in other regions point to an important role of direct multiphoton transitions to levels containing quanta of the neighboring combination mode ν5+ν6 (870 cm−1) besides ν3 quanta. On the short wavelength side of ν3, the analogous transitions involve the ν2+ν6 mode (991 cm−1). The wings, and thus the spectral shape of Pd, in the ν3 region are also governed by them. They depend more strongly on temperature than stepwise transitions, because the intermediate near-resonances favor the high rotational states.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.455908
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  • 7
    Electronic Resource
    Electronic Resource
    Rovibronic energy transfer from N2(a 1πg) to CO(A 1π) studied by laser REMPI spectroscopy (1987)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 87 (1987), S. 2742-2749 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: The collision-induced electronic energy transfer N2(a 1πg,v′) +CO(X 1Σ+,v″=0) →N2(X 1Σ+g,v″) +CO(A 1πg,v′)+ΔE is studied in a gas cell. N2(a 1πg,v′, J′) is prepared by two-photon (2hν1) absorption from the ground state. CO(A 1πg,v′, J′) is probed by two-photon (hν1+hν2) ionization via CO(B 1Σ+) as the resonant intermediate state. Experiments show that the overall energy transfer cross sections exceed that of gas kinetic collisions by a factor of 3–4. The energy mismatch ΔE is the determining factor controlling the branching ratio from one N2(1πg,v′) donor to different vibrational levels of CO(A 1π,v′). For small values of ΔE, CO(A 1πg,v′, J′) shows a Boltzmann-like rotational level population. Its rotational temperature scales with ΔE. About 28% of the excess energy funnels into the rotation of CO(A 1π). An explanation for the observed rotational distribution of CO* and the energy transfer mechanism is given. The rate constants are analyzed in terms of the surprisal.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.453061
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  • 8
    Electronic Resource
    Electronic Resource
    A laser-induced fluorescence and information-theory investigation of energy transfer processes in benzene–argon collisions (1985)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 82 (1985), S. 810-821 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: This paper reports the results of an extensive study of the internal energy-transfer processes that occur in benzene–argon collisions. We used laser-induced fluorescence and information theory for determining the energy-transfer rates between internal states of benzene in the ground electronic state (1A1g). The method provides an estimate for the rate of rotational relaxation. It gives a measure of the fraction of molecules that absorb the laser radiation at a frequency near the center of the ν18 absorption band of benzene. The use of information theory gives estimates for all of the vibrational energy transfer rates. These fit the experimental data reasonably well. However, some of the data do deviate from the information theory model. This suggests that the statistical assumptions of the model are not sufficiently restrictive. One such restriction may be in the number of vibration quanta changing per collision..
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.448507
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  • 9
    Electronic Resource
    Electronic Resource
    UV laser photochemistry and diborane at 193 nm: Quantum yield for BH"3 production
    Amsterdam : Elsevier
    Journal of Photochemistry 32 (1986), S. 139-142 
    Details
    ISSN: 0047-2670
    Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://linkinghub.elsevier.com/retrieve/pii/0047-2670(86)87002-2
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  • 10
    Electronic Resource
    Electronic Resource
    A guided-ion beam study of the hydrogen atom transfer reaction of state-selected N+2 with H2 at collision energies ranging from subthermal to 2 eV (c.m.) (1995)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 102 (1995), S. 214-225 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: This article presents detailed internal and kinetic energy dependent cross sections and reaction rates for the hydrogen atom transfer processes N+2(X 2Σ+g, v+=0–4, J+=2)+H2→N2H++H, which were obtained under single-collision conditions in a guided-ion beam/scattering gas experiment. Preparation of ions in specific states relied on single-color excitation within a resonantly enhanced (2+1) multiphoton ionization scheme. The translational energy of the ions, Elab, was varied from 0.1 eV to approximately 30 eV. A small activation barrier impedes the reaction. Vibronic state preparation of the nitrogen ion is influential on the nature of the energy surface—N+2+H2 or H+2+N2—along which the H atom transfer proceeds. Calculations of model potential energy surfaces suggest that the reaction pathway must involve several exoergic and endoergic channels which open successively as the collision energy increases. A purely collision determined cross section—as would be evidenced by the E−1/2 dependence formulated in the Langevin–Gioumousis–Stevenson model—is observed only within a narrow window of kinetic energies. © 1995 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.469394
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