://000083685400006},
author = {Cavigliasso, G. and Chong, D. P.}
}
@article {4391,
title = {Valence orbital electron momentum distributions for oxygen: comparison of EMS measurements with theory},
journal = {Chem. Phys.},
volume = {230},
number = {2-3},
year = {1998},
note = {ISI Document Delivery No.: ZR243Times Cited: 19Cited Reference Count: 72},
month = {May},
pages = {153-186},
type = {Article},
abstract = {The valence shell binding energy spectra and orbital electron momentum profiles of O-2 have been measured by energy dispersive multichannel electron momentum spectroscopy at an impact energy of 1200 eV + binding energy. The effects of electron correlation on the valence binding energy spectrum are investigated using multi-reference singles and doubles configuration interaction calculations. The presently reported experimental momentum profiles of O-2 display considerably improved statistics compared with previously published EMS results. The measured momentum profiles are compared with cross sections calculated using both unrestricted and restricted open shell Hartree-Fock methods with basis sets ranging from minimal to near Hartree-Fock limit in quality. In addition, the effects of correlation and relaxation on the calculated momentum profiles are investigated using multi-reference singles and doubles configuration interaction calculations of the full ion-neutral overlap distributions. Electron correlation effects in the ground state are further examined using several density functional approaches for the momentum profiles. The present EMS measurements and MRSD-CI calculations clearly show that the binding energy peak at similar to 27.3 eV has significant contributions from both (4) Sigma(u)(-) and (2) Sigma(u)(-) processes in contrast to earlier assignments which have attributed this peak to the C-2 Sigma(u)(-) State alone. Similarly, the binding energy peak at 33 eV is shown to be due to (2) Sigma(u)(-) rather than earlier assignments of (2) Pi(u) character. (C) 1998 Elsevier Science B.V. All rights reserved.

},
keywords = {CALCULATIONS, CONFIGURATION-INTERACTION CALCULATIONS, CORRELATED MOLECULAR, CORRELATION ENERGIES, DENSITY-FUNCTIONAL THEORY, DFT calculations, GAUSSIAN-BASIS SETS, HARTREE-FOCK LIMIT, OPEN-SHELL MOLECULES, PHOTOELECTRON-SPECTROSCOPY, PHOTOIONIZATION CROSS-SECTIONS},
isbn = {0301-0104},
url = {://000073954600002},
author = {Rolke, J. and Zheng, Y. and C. E. Brion* and Wang, Y. A. and Davidson, E. R.}
}
@article {3065,
title = {PURE ROTATIONAL SPECTRUM OF, AND POTENTIAL-ENERGY SURFACE FOR, THE AR-N-2 VAN-DER-WAALS COMPLEX},
journal = {Faraday Discussions},
volume = {97},
year = {1994},
note = {ISI Document Delivery No.: QB093Times Cited: 22Cited Reference Count: 84Meeting on Structure and Dynamics of Van der Waal ComplexesAPR 06-08, 1994DURHAM, ENGLAND},
pages = {105-118},
type = {Proceedings Paper},
abstract = {Pure rotational spectra of three isotopomers of the Van der Waals complex Ar-N-2 have been investigated in the frequency range 3.5-20 GHz, using a pulsed molecular beam cavity microwave Fourier-transform spectrometer. Rotational constants and quartic and sextic centrifugal distortion constants have been obtained, along with N hyperfine constants. The spectra of Ar-N-14(2) and Ar-N-15(2) indicate equivalence of the nitrogen nuclei, and thus confirm C-2v symmetry for the complexes. The measured transition frequencies and the derived constants have been used to test the best available literature potential-energy surfaces for the Ar-N-2 interaction. For this purpose rotational transition frequencies and expectation values of other properties were calculated and compared with the corresponding values from the microwave experiments. A refined version of one of the surfaces has been generated by inclusion of the microwave results.},
keywords = {AR, CALCULATIONS, ELASTIC-SCATTERING MEASUREMENTS, FOCK SCF, INFRARED-SPECTRUM, INTER-MOLECULAR FORCES, INTERMOLECULAR FORCES, N2-AR, RANGE DISPERSION COEFFICIENTS, TRANSFORM MICROWAVE SPECTROSCOPY, VANDERWAALS MOLECULES},
isbn = {0301-7249},
url = {://A1994QB09300009},
author = {Jager, W. and Gerry, M. C. L. and Bissonnette, C. and McCourt, F. R. W.}
}
@article {7172,
title = {KINETIC ISOTOPE EFFECTS IN GAS-PHASE MUONIUM REACTIONS},
journal = {Acs Symposium Series},
volume = {502},
year = {1992},
note = {ISI Document Delivery No.: JY550Times Cited: 16Cited Reference Count: 101},
pages = {111-137},
type = {Review},
abstract = {The study of the reaction dynamics of muonium (Mu), an ultralight isotope of hydrogen ((m)Mu/(m)H almost-equal-to 1/9), provides a sensitive measure of mass effects in chemical reactions. The remarkable mass difference between Mu and the other hydrogen isotopes produces large kinetic isotope effects, providing a rigorous test of calculated potential energy surfaces (PES) and reaction rate theories. The low Mu mass also necessitates careful consideration of quantum effects, i.e. tunneling in the reaction coordinate. A review of recent results in gas phase Mu chemistry is presented, including comparison with relevant H chemistry and calculated PESs, where available. The magnitude and direction of the kinetic isotope effect is shown to be a sensitive function of the PES, particularly the height and position of the saddle point.},
keywords = {+ HBR(DBR) ABSTRACTION, ACTION, ADDITION-REACTIONS, CALCULATIONS, CHARGE-EXCHANGE, COLLISIONS, LOW-TEMPERATURES, POTENTIAL-ENERGY SURFACES, PRESSURE-DEPENDENCE, RESONANCE, THERMAL RATE CONSTANTS, TRANSITION-STATE THEORY, TUNNELING PATHS},
isbn = {0097-6156},
url = {://A1992JY55000008},
author = {Baer, S. and Fleming, Donald G. and Arseneau, D. and Senba, M. and Gonzalez, A.}
}
@article {7248,
title = {MUONIUM REACTION-KINETICS WITH THE HYDROGEN HALIDE GASES},
journal = {Journal of Chemical Physics},
volume = {97},
number = {9},
year = {1992},
note = {ISI Document Delivery No.: JX295Times Cited: 14Cited Reference Count: 80},
month = {Nov},
pages = {6309-6321},
type = {Article},
abstract = {The reaction rates of the muonium (Mu) atom with HBr and HI in approximately 1 atm N2 moderator have been measured over the temperature range 160-490 K using the muSR technique. While both abstraction and exchange reactions are possible, only the abstraction reaction should be observable, being moderately exothermic. Comparisons with the corresponding H(D) reactions reveal small kinetic isotope effects in both reactions, which do not vary strongly with temperature (k(Mu)/k(H) almost-equal-to 3.5 near 300 K), consistent with the (classical) ratio of mean velocities. Surprisingly, quantum tunneling, normally facile for similarly exothermic reactions of the ultralight Mu atom (m(Mu)/M(H) almost-equal-to 1/9), appears to be of little importance here. This despite the fact that the (temperature-independent) experimental activation energies are much less than the expected vibrationally adiabatic barrier heights (estimated to be almost-equal-to 1. 5 kcal mol-1) and, particularly in the case of Mu + HI, much less than the corresponding H-atom activation energy: 0. 13 +/- 0.03 vs 0.70 +/- 0. 3 kcal mol-1. In the case of reactions with HBr, the experimental Mu- and H-atom activation energies are much more similar: 0. 51 +/- 0.03 and 0.74 +/- 0. 12 kcal mol-1, respectively, over comparable temperature ranges. These data pose a conundrum in which several compensating effects related to the much lighter Mu-atom mass seem to be involved. Theoretical calculations are urgently required. In our view the topography of the potential-energy surface(s) for H-2X is poorly known, particularly in the region of the barrier. It may be that the abstraction barriers for both Mu + HI and Mu + HBr are considerably later and even smaller than current calculations indicate, resulting in a cancellation of the effects of zero-point-energy shifts and quantum tunneling at the transition state. Differences in skewing angles between Mu and H + HX could favor a shorter tunneling path for the H-atom reaction, possibly compensating for its heavier mass. Steric or rebound effects from "bottlenecks" on the (mass-weighted) potential surfaces for Mu reactivity may also play some role. An upper limit for the 300 K reaction rate of Mu + HCI is given as well. In contrast to both HBr and HI, this reaction is quite endothermic and hence exhibits an inverse kinetic isotope effect (k(Mu) much less than k(H)).},
keywords = {ABSTRACTION REACTIONS, CALCULATIONS, CHEMICAL-REACTIONS, EV COLLISION ENERGY, EXCHANGE-REACTIONS, H+HX COLLISIONS, ISOTOPIC, POTENTIAL-ENERGY SURFACE, QUANTUM-MECHANICAL, RATE CONSTANTS, TRANSITION-STATE THEORY, VARIANTS},
isbn = {0021-9606},
url = {://A1992JX29500038},
author = {Gonzalez, A. C. and Tempelmann, A. and Arseneau, D. J. and Fleming, Donald G. and Senba, M. and Kempton, J. R. and Pan, J. J.}
}