A generalized formulation of canonical transformations and spectra are used to investigate the concept of a canonical potential strictly within the Born-Oppenheimer approximation. Data for the most accurate available ground electronic state pairwise intermolecular potentials in H2, HD, D2, HeH(+), and LiH are used to rigorously evaluate such transformations. The corresponding potentials are generated explicitly using parameters calculated with algebraic functions from that of the single canonical potential of the simplest molecule, H2(+). The efficacy of this approach is further tested by direct comparison of the predicted eigenvalues of all vibrational states in the selected molecular systems considered with the corresponding most accurately known Born-Oppenheimer eigenvalues currently available. Deviations are demonstrated to be less than 2 cm(-1) for all vibrational states in H2, HD, D2, HeH(+), and LiH, with an average standard deviation of 0.27 cm(-1) for the 87 states considered. The implications of these results for molecular quantum chemistry are discussed.

A fully three-dimensional morphed potential energy surface is reported for Ar:HBr. The morphed potential was obtained from parametrized scaling and shifting transformations of an ab initio potential. The optimum parameters of the morphed potential were determined by a regularized nonlinear least-squares fit to available experimental data. The rovibrational dynamics of the complex were computed using an adiabatic separation of the H-Br intramolecular stretching mode from the intermolecular modes of the system. The ground rovibrational state of the morphed potential was found to have the hydrogen-bound structure Ar-HBr. This state was 10.99 cm Ϫ1 more stable than the corresponding state having the van der Waals structure, Ar-BrH, in agreement with experimental data. However, the global minimum of the morphed potential was found to have the van der Waals structure, Ar-BrH. This structure was 20.9 cm Ϫ1 lower in energy than the local minimum having the hydrogen-bound structure, Ar-HBr.

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Effect of solvent on molecular conformation: Microwave spectra and structures of 2-aminoethanol van der Waals complexesAb initio relativistic all-electron calculation of the Ar-I 2 ground state potential A study of the ArCl 2 Van der Waals complex: Ab initio-based potential energy surfaces, the relative stability of conformers, and the "hidden" microwave spectrumThe structure and ground state dynamics of the atom-diatom dimer interaction between Ar and HI has been investigated by microwave and near infrared supersonic jet spectroscopy. Ab initio molecular orbital calculations were used to provide greater insight into the nature of the interaction. The ground state is shown to be in the isomeric form Ar-IH with R cm ϭ3.9975(1) Å, ϭ149.33(1)°for the normal isotopomer and R cm ϭ3.9483(1) Å, ϭ157.11(1)°for Ar-ID. The potential surface from an ab initio molecular orbital calculation was scaled and shifted to yield a nonlinear least-squares fit of the rovibrational state energies to the experimental data. The ground state potential energy surface obtained in this manner has a barrier between the Ar-IH and Ar-HI isomers of 88.5 cm Ϫ1 with respect to the global minimum. Such calculations are also used to predict the presence of localized states in the secondary minimum associated with isomers Ar-HI and Ar-DI. Attempts to experimentally identify transitions associated with the latter were unsuccessful. The ground state, Ar-IH isomeric structure, contrasts with the corresponding ground state of the other members of the homologous series Ar-HX ͑XϭF, Cl, and Br͒ in which the Ar is bound to the proton.

Application of surface wave plasmas as an innovative technology for the destruction and removal of perfluorocompounds (PFC) emanating from semiconductor fabrication tools is demonstrated. The destruction of parts per thousand (ppt) concentrations of hexafluoroethane, C2F6, in oxygen and natural gas mixtures has been investigated as a function of microwave power in a low-pressure plasma reactor at 11.3 Torr. Effluent analysis included the determination of destruction and removal efficiencies (DRE) and product distributions by Fourier transform infrared spectroscopy and mass spectrometry. Destruction and removal efficiences of up to 99.6% for C2F6 were achieved using applied microwave powers from 500 to 2000 W, which corresponded to millisecond range residence times within the plasma. Product analysis indicated that hexafluoroethane conversion was limited to low molecular weight gases such as CO2, CO, COF2, H2O, and HF. CF4 was not produced as a plasma byproduct in any significant quantities. These investigations indicate that surface wave plasma destruction of perfluorocompounds at the point of use is a viable nonintrusive abatement technology for application to semiconductor manufacturing tools.