@article {2482, title = {Fourier transform microwave spectrum of and Born-Oppenheimer breakdown effects in tungsten monoxide, WO}, journal = {Canadian Journal of Physics}, volume = {87}, number = {5}, year = {2009}, note = {ISI Document Delivery No.: 494RVTimes Cited: 0Cited Reference Count: 33Krumrey, Christine Cooke, Stephen A. Russell, Douglas K. Gerry, Michael C. L.}, month = {May}, pages = {567-573}, type = {Article}, abstract = {Rotational transitions of eight isotopomers of tungsten monoxide, WO, in its X0(+) ground electronic state, have been measured in the frequency range 22-26 GHz, using a cavity Fourier transform microwave spectrometer. The samples were prepared by laser ablation of W metal in the presence of O-2 and stabilized in pulsed supersonic jets of Ne or Ar. Only the J = 1-0 transition was accessible within the frequency range of the spectrometer. It was measured for the ground (nu = 0) and two excited (nu = 1, 2) vibrational states. Hyperfine structure due to W-183 nuclear spin-rotation coupling was found for (WO)-W-183. The overall spectral fit used a Dunham-type expression including Born-Oppenheimer breakdown parameters. Only the nu = 0 and 1 states could be fit to the measurement accuracy because of a small perturbation of the nu = 2 state. It was necessary to account for the finite nuclear size of the W nucleus in the fit. The resulting parameter V-01(W) agreed well with a value calculated using density functional theory. Equilibrium internuclear distances re have been evaluated.}, keywords = {COUPLING CASE C, DIATOMIC-MOLECULES, DUNHAM COEFFICIENTS, ENERGY, FIELD SHIFT, INFRARED-SPECTRA, ISOTOPE DEPENDENCE, PB-CHALCOGENIDES, ROTATIONAL SPECTRUM, TL-HALIDES}, isbn = {0008-4204}, url = {://000269834000014}, author = {Krumrey, C. and Cooke, S. A. and Russell, D. K. and Gerry, M. C. L.} } @article {2165, title = {An efficient mapped pseudospectral method for weakly bound states: vibrational states of He-2, Ne-2, Ar-2 and Cs-2}, journal = {Journal of Physics B-Atomic Molecular and Optical Physics}, volume = {41}, number = {18}, year = {2008}, note = {ISI Document Delivery No.: 347PITimes Cited: 2Cited Reference Count: 54Lo, Joseph Q. W. Shizgal, Bernie D.}, month = {Sep}, pages = {13}, type = {Article}, abstract = {This paper reports the application of pseudospectral methods to the calculation of the bound states of He-2, Ne-2, Ar-2 and Cs-2. The calculation of the uppermost loosely bound states, only one for He-2, presents a challenge for most numerical methods. We employ the quadrature discretization method which is a collocation based on quadrature points defined with weight functions that approximate the ground states. A mapping procedure is proposed that greatly improves the convergence of the uppermost states that are very loosely bound and characterized by very diffuse eigenfunctions. Comparisons with the results with other methods and experiment are also carried out wherever possible.}, keywords = {BASIS FUNCTIONS, DIATOMIC-MOLECULES, DIMERS, DISCRETE, HELIUM DIMER, LAGRANGE-MESH METHOD, LONG-RANGE MOLECULES, NONCLASSICAL, QUADRATURE DISCRETIZATION METHOD, QUANTUM-MECHANICAL PROBLEMS, RARE-GAS, ULTRAVIOLET-LASER SPECTROSCOPY, VARIABLE REPRESENTATION}, isbn = {0953-4075}, url = {://000259153100008}, author = {Lo, J. Q. W. and Shizgal, B. D.} } @article {1088, title = {The influence of nuclear volume and electronic structure on the rotational energy of platinum monoxide, PtO}, journal = {Physical Chemistry Chemical Physics}, volume = {7}, number = {12}, year = {2005}, note = {ISI Document Delivery No.: 942UOTimes Cited: 11Cited Reference Count: 56}, month = {Jun}, pages = {2453-2459}, type = {Article}, abstract = {The pure rotational spectra of seven isotopic species of platinum monoxide have been measured with a cavity pulsed jet Fourier-transform microwave spectrometer. The molecules were prepared by laser ablation of Pt foil in the presence of O-2 and stabilized in a supersonic jet of argon. A multi-isotopomer Dunham-type analysis of the spectra produced values for Y-01 and Y-11, along with unusually large values for Born-Oppenheimer breakdown (BOB) parameters for both Pt and O atoms. The values of the BOB parameters have been rationalized in terms of the molecular electronic structure and finite nuclear size (field shift) effects. A large negative Pt-195 effective nuclear spin-rotation constant has been rationalized in terms of the electron-nucleus dipole dipole hyperfine constant. Precise internuclear separations have been evaluated.}, keywords = {COUPLING CASE C, DIATOMIC-MOLECULES, DIPOLE MOMENT, DUNHAM COEFFICIENTS, EMISSION-SPECTRUM, FIELD SHIFT, FOURIER-TRANSFORM SPECTROSCOPY, GROUND-STATE, HYPERFINE CONSTANTS, PB-CHALCOGENIDES}, isbn = {1463-9076}, url = {://000230308600007}, author = {Cooke, S. A. and Gerry, M. C. L.} } @article {1089, title = {Pure rotational spectra of LuF and LuCl}, journal = {Physical Chemistry Chemical Physics}, volume = {7}, number = {13}, year = {2005}, note = {ISI Document Delivery No.: 938CUTimes Cited: 8Cited Reference Count: 56}, pages = {2570-2578}, type = {Article}, abstract = {The pure rotational spectra of two isotopic species of LuF and three of LuCl have been measured in the frequency range 5-17 GHz using a cavity pulsed jet Fourier transform microwave spectrometer. The samples were prepared by laser ablation of Lu metal in the presence of SF6 or Cl-2, and stabilized in supersonic jets of Ar. Spectra of molecules in states having v = 0, 1, and 2 have been measured, to produce rotational constants and centrifugal distortion constants, along with hyperfine constants for all the nuclei. Dunham-type. fits for LuCl produced a Born-Oppenheimer breakdown parameter for Cl. Although a theoretical calculation showed that Lu in LuCl should have a significant field shift effect parameter, it could not be determined from the spectrum. Equilibrium internuclear distances, re, and dissociation energies have been evaluated for both molecules. The nuclear quadrupole coupling constants are discussed in terms of the molecular electronic structure.}, keywords = {BORN-OPPENHEIMER APPROXIMATION, DIATOMIC-MOLECULES, DUNHAM COEFFICIENTS, FIELD SHIFT, HYPERFINE CONSTANTS, ISOTOPE DEPENDENCE, METAL-POOR, NEUTRON-CAPTURE ELEMENTS, NUCLEAR-CHARGE RADII, TRANSFORM MICROWAVE SPECTROSCOPY}, isbn = {1463-9076}, url = {://000229978300005}, author = {Cooke, S. A. and Krumrey, C. and Gerry, M. C. L.} } @article {822, title = {Internuclear distance and effects of Born-Oppenheimer breakdown for PtS, determined from its pure rotational spectrum}, journal = {Journal of Chemical Physics}, volume = {121}, number = {8}, year = {2004}, note = {ISI Document Delivery No.: 845HYTimes Cited: 13Cited Reference Count: 55}, month = {Aug}, pages = {3486-3494}, type = {Article}, abstract = {Platinum monosulfide PtS has been prepared in its X0(+) ground electronic state by laser ablation of Pt in the presence of H2S. The rotational spectra of eight isotopic species have been measured with a cavity pulsed jet Fourier-transform microwave spectrometer. Spectral analysis using a multi-isotopomer Dunham-type expression produced values for Y-01, Y-02, Y-11, and Y-21, along with large values for Born-Oppenheimer breakdown (BOB) parameters for both atoms of the molecule. The BOB parameters are rationalized in terms of the molecular electronic structure and nuclear field shift effects. A large negative Pt-195 nuclear spin-rotation constant has been rationalized in terms of the electron-nucleus dipole-dipole hyperfine constant. The equilibrium bond length in the Born-Oppenheimer approximation has been evaluated. (C) 2004 American Institute of Physics.}, keywords = {BISMUTH IODIDE BII, COUPLING CASE C, DIATOMIC-MOLECULES, DUNHAM COEFFICIENTS, ELECTRIC-DIPOLE MOMENT, EMISSION-SPECTROSCOPY, FIELD SHIFT, FOURIER-TRANSFORM SPECTROSCOPY, HYPERFINE CONSTANTS, NUCLEAR-CHARGE, RADII}, isbn = {0021-9606}, url = {://000223234200017}, author = {Cooke, S. A. and Gerry, M. C. L.} } @article {826, title = {Microwave spectra, nuclear field shift effects, geometries and hyperfine constants of bismuth mononitride, BiN, and bismuth monophosphide, BiP}, journal = {Journal of Molecular Structure}, volume = {695}, year = {2004}, note = {ISI Document Delivery No.: 827SVTimes Cited: 11Cited Reference Count: 66Sp. Iss. SI}, month = {Jun}, pages = {13-22}, type = {Article}, abstract = {The diatomic molecules BiN and BiP have been prepared using a laser ablation technique and studied by Fourier transform microwave spectroscopy in the frequency range 7-22 GHz. For BiN, only the J = 1-0 transition fell within this range. Transitions for the ground and first excited vibrational states have been observed for both (BiN)-N-14 and (BiN)-N-15. For BiP, which has only one isotopomer, the transitions J{\textquoteright}-J" = 1-0. 2-1 and 3-2 have been observed, but only for the ground vibrational state. Hyperfine structure has been observed for both nuclei in both molecules the Bi-209 nuclear quadrupole coupling constants show that the electronic structures are similar for the two molecules. Improved bond lengths have been obtained for both molecules. Density functional methods have been used to estimate the electron density at the bismuth nucleus in each molecule and hence allow an estimate of the uncertainty due to field shift effects in the experimentally derived bond lengths. (C) 2003 Elsevier B.V. All rights reserved.}, keywords = {BII, BiN, BiP, BORN-OPPENHEIMER APPROXIMATION, Born-Oppenheimer breakdown, DIATOMIC-MOLECULES, DUNHAM COEFFICIENTS, FOURIER-TRANSFORM SPECTROSCOPY, GROUND-STATE, HIGH-RESOLUTION, HYPERFINE, IODIDE, ISOTOPE DEPENDENCE, microwave spectra, MOMENTS, nuclear field shift effects, QUADRUPOLE, ROTATIONAL SPECTRUM, STRUCTURE}, isbn = {0022-2860}, url = {://000221922000003}, author = {Cooke, S. A. and Michaud, J. M. and Gerry, M. C. L.} } @article {821, title = {The pure rotational spectra and hyperfine constants of SbN and SbP}, journal = {Physical Chemistry Chemical Physics}, volume = {6}, number = {19}, year = {2004}, note = {ISI Document Delivery No.: 858PQTimes Cited: 14Cited Reference Count: 54}, pages = {4579-4585}, type = {Article}, abstract = {The pure rotational spectra of antimony mononitride, SbN, and antimony monophosphide, SbP, have been recorded within the frequency range 6-26 GHz, using a cavity pulsed jet Fourier transform microwave spectrometer. The molecules were prepared by laser ablation of Sb and reaction of the resulting plasma with suitable precursors in the backing gas of the jet. For SbN the J = 1-0 transition was measured for the vibrational ground state of four isotopomers, two of which were also seen in the v = 1 excited state. For SbP the J = 1-0 and 2-1 transitions have been observed for two isotopomers in the ground plus v = 1 and v = 2 excited vibrational states. Accurate spectroscopic constants, including Born-Oppenheimer breakdown terms for Sb and N, have been obtained from the spectra. Precise equilibrium bond lengths r(e) have been determined. Hyper. ne constants including nuclear quadrupole coupling constants and nuclear spin-rotation constants have been evaluated for both molecules, and are compared with the results of density functional calculations.}, keywords = {APPROXIMATION, DENSITY-FUNCTIONAL THEORY, DEPENDENCE, DIATOMIC-MOLECULES, DUNHAM COEFFICIENTS, FIELD SHIFT, ISOTOPE, NMR CHEMICAL-SHIFTS, NUCLEAR MAGNETIC SHIELDINGS, ORDER REGULAR, QUADRUPOLE-MOMENT, SPIN-ROTATION}, isbn = {1463-9076}, url = {://000224204600010}, author = {Cooke, S. A. and Gerry, M. C. L.} } @article {824, title = {The rotational spectrum, nuclear field shift effects, Pt-195 nuclear spin-rotation constant, and electric dipole moment of PtSi}, journal = {Journal of Molecular Spectroscopy}, volume = {223}, number = {2}, year = {2004}, note = {ISI Document Delivery No.: 771HGTimes Cited: 11Cited Reference Count: 52}, month = {Feb}, pages = {185-194}, type = {Article}, abstract = {The pure rotational spectrum of the X(1)Sigma(+) ground electronic state of platinum monosilicide has been measured for nine isotopomers. For the most abundant isotopomer, (PtSi)-Pt-194-Si-28, the J = 1-0 and the J = 2-1 transitions were recorded up to the fourth vibrationally excited state. The data set obtained enabled a multi-isotopomer fit to a Dunham-type expression and the constants Y-01, Y-02, Y-11, Y-21, and Y-31 were determined. In the process of fitting the data it was necessary to include Born-Oppenheimer breakdown correction terms and the values and significance of these terms are discussed. Strong evidence is presented indicating within the rotational spectrum the presence of field shift effects due to the finite size of the Pt nucleus. The nuclear spin-rotation constant, C-I(Pt-195) is found to be 30.98(157)kHz in the ground vibrational state. Hyperfine structure arising from the Si-29 nucleus was not observed. The measurement of Stark shifts in the rotational spectrum of PtSi has enabled the determination of the dipole moments for the (PtSi)-Pt-194-Si-28 and (PtSi)-Pt-196-Si-28 isotopomers. Published by Elsevier Inc.}, keywords = {BORN-OPPENHEIMER APPROXIMATION, CHARGE RADII, DEPENDENCE, DIATOMIC-MOLECULES, DUNHAM COEFFICIENTS, EXCHANGE, HYPERFINE CONSTANTS, ISOTOPE, STATES, TRANSFORM MICROWAVE SPECTROSCOPY, WAVE SPECTRA}, isbn = {0022-2852}, url = {://000188779100010}, author = {Cooke, S. A. and Gerry, M. C. L. and Brugh, D. J. and Suenram, R. D.} } @article {355, title = {The pure rotational spectrum, geometry and hyperfine constants of hafnium monosulfide, HfS}, journal = {Journal of Molecular Spectroscopy}, volume = {216}, number = {1}, year = {2002}, note = {ISI Document Delivery No.: 622VATimes Cited: 12Cited Reference Count: 47}, month = {Nov}, pages = {122-130}, type = {Article}, abstract = {{The pure rotational spectra of seven isotopomers of hafnium monosulfide have been measured for several vibrational states. For the most abundant isotopomer, (HfS)-Hf-180-S-32, the J = 1 - 0}, keywords = {BORN-OPPENHEIMER APPROXIMATION, DIATOMIC-MOLECULES, DIPOLE-MOMENTS, DUNHAM COEFFICIENTS, EMISSION-SPECTRUM, FOURIER-TRANSFORM SPECTROSCOPY, HIGH-RESOLUTION, ISOTOPE DEPENDENCE, MICROWAVE SPECTROSCOPY, STATES}, isbn = {0022-2852}, url = {://000179666700015}, author = {Cooke, S. A. and Gerry, M. C. L.} } @article {4471, title = {Rotational spectra and hyperfine constants of ZrO and ZrS}, journal = {Journal of Chemical Physics}, volume = {110}, number = {22}, year = {1999}, note = {ISI Document Delivery No.: 199FFTimes Cited: 32Cited Reference Count: 49}, month = {Jun}, pages = {10715-10724}, type = {Article}, abstract = {The pure rotational spectra of ZrO and ZrS have been recorded using cavity Fourier transform microwave spectroscopy in the frequency range 9-26 GHz. The molecules were generated by laser ablation of a solid Zr rod in the presence of 0.05\% of O-2 or H2S, respectively, in either argon or neon. Rotational spectra of five previously unobserved isotopomers of ZrO in the X(1)Sigma(+) state have been measured. Spectra for all five (ZrS)-S-32 isotopomers and for the (ZrS)-Zr-90-S-34 isotopomer in natural abundance have also been measured; this is the first report of pure rotational transitions for ZrS. Transitions in several excited vibrational states were also measured for the most abundant isotopomers of both species. Atomic mass-dependent Born-Oppenheimer breakdown correction terms were determined by fitting the data obtained for each molecule to a Dunham-like expression. Values for the equilibrium bond lengths of the two species were also calculated from the results of these fits. For both the (ZrS)-Zr-91-S-32 and (ZrO)-Zr-91-O-16 isotopomers, nuclear hyperfine structure due to the zirconium nucleus was observed and values for eQ(q0) (Zr-91) and C-I (Zr-91) have been determined. A rotational transition in the low lying a (3)Delta state of ZrS has also been observed. (C) 1999 American Institute of Physics. [S0021-9606(99)00121-X].}, keywords = {BORN-OPPENHEIMER APPROXIMATION, COEFFICIENTS, DEPENDENCE, DIATOMIC-MOLECULES, DIPOLE-MOMENTS, DUNHAM, FOURIER-TRANSFORM SPECTROSCOPY, ISOTOPE, LOW-TEMPERATURE, METAL-OXIDES, REFRACTORY MOLECULES, ZIRCONIUM OXIDE}, isbn = {0021-9606}, url = {://000080469200010}, author = {Beaton, S. A. and Gerry, M. C. L.} } @article {4417, title = {A semiclassical approach to intense-field above-threshold dissociation in the long wavelength limit. II. Conservation principles and coherence in surface hopping}, journal = {Journal of Chemical Physics}, volume = {109}, number = {14}, year = {1998}, note = {ISI Document Delivery No.: 125BETimes Cited: 28Cited Reference Count: 24}, month = {Oct}, pages = {5747-5760}, type = {Article}, abstract = {This paper is a companion to our recently published semiclassical formalism for treating time-dependent Hamiltonians [J. Chem. Phys, 105, 4094 (1996)], which was applied to study the dissociation of diatomic ions in intense laser fields. Here two fundamental issues concerning this formalism are discussed in depth: conservation principles and coherence. For time-dependent Hamiltonians, the conservation principle to apply during a trajectory hop depends upon the physical origin of the electronic transition, with total energy conservation and nuclear momentum conservation representing the two limiting cases. It is shown that a]applying an inappropriate scheme leads to unphysical features in the kinetic energy of the dissociation products. A method is introduced that smoothly bridges the two limiting cases and applies the physically justified conservation scheme at all times. It is also shown that the semiclassical formalism can predict erroneous results if the electronic amplitudes for well-separated hops are added coherently. This is a fundamental problem with the formalism which leads to unphysical results if left unattended. Alternative schemes are introduced for dealing with this problem and their accuracies are assessed. Generalization of the well-known Landau-Zener formula to the time-dependent Hamiltonian case is derived, which allows one to significantly decrease the computational overhead involved with the numerical implementation of the semiclassical method. Finally, we show that in strong-field molecular dissociation a trajectory can {\textquoteright}{\textquoteright}surf" a moving avoided crossing. In this case the hopping probability is a sensitive function of the interference between two closely spaced avoided crossing regions. (C) 1998 American Institute of Physics.}, keywords = {COULOMB EXPLOSION, DIATOMIC-MOLECULES, ENHANCED, H-2(+), IONIZATION, LASER FIELDS, MODEL, MOLECULAR-DYNAMICS, PHOTODISSOCIATION, QUANTUM DECOHERENCE, TRANSITIONS}, isbn = {0021-9606}, url = {://000076216900008}, author = {Thachuk, M. and Ivanov, M. Y. and Wardlaw, D. M.} } @article {3572, title = {ROTATIONAL SPECTRA OF THE MIXED RARE-GAS DIMERS NE-KR AND AR-KR}, journal = {Journal of Chemical Physics}, volume = {103}, number = {8}, year = {1995}, note = {ISI Document Delivery No.: RP715Times Cited: 29Cited Reference Count: 40}, month = {Aug}, pages = {2827-2833}, type = {Article}, abstract = {Pure rotational spectra of several isotopomeric species of the rare gas dimers Ne-Kr and Ar-Kr have been measured using a pulsed jet cavity microwave Fourier transform spectrometer. Equilibrium internuclear distances have been evaluated by taking advantage of the isotopic data, for both these dimers and three Xe-containing dimers, whose spectra were reported earlier [Jager et al., J. Chem. Phys. 99, 919(1993)]. The dipole moments have been estimated using the {\textquoteright}{\textquoteright}pi/2-pulse{\textquoteright}{\textquoteright} excitation condition. Kr-83 nuclear quadrupole hyperfine structure has been observed in some rotational transitions of Ne-20-Kr-83 and of Ar-Kr-83, and the corresponding quadrupole coupling constants have been derived. (C) 1995 American Institute of Physics.}, keywords = {CONSTANTS, DEPENDENCE, DIATOMIC-MOLECULES, DUNHAM COEFFICIENTS, EXCITED-STATES, FABRY-PEROT CAVITY, ISOTOPE, POTENTIALS, TRANSFORM MICROWAVE SPECTROSCOPY, ULTRAVIOLET-LASER SPECTROSCOPY, XE}, isbn = {0021-9606}, url = {://A1995RP71500006}, author = {Xu, Y. J. and Jager, W. and Djauhari, J. and Gerry, M. C. L.} } @article {6988, title = {THEORETICAL-STUDY OF THE HYPERFINE PARAMETERS OF OH}, journal = {Journal of Chemical Physics}, volume = {94}, number = {5}, year = {1991}, note = {ISI Document Delivery No.: FA778Times Cited: 20Cited Reference Count: 32}, month = {Mar}, pages = {3700-3706}, type = {Article}, abstract = {The magnetic hyperfine parameters of (OH)-O-17 are studied as a function of the one- and n-particle spaces. All of the parameters, except the spin density on oxygen, b(F)(O), are well described by modest levels of theory. Thus, we have directed much of our effort to understanding the computational requirements for accurately determining b(F)(O). Full configuration-interaction (FCI) calculations in six Gaussian basis sets give unambiguous results for the effect of uncontracting the oxygen s and p basis sets, of adding diffuse s and p functions, and of adding polarization functions to oxygen. FCI calculations in a [6s 2p 1d /2s] contracted basis give a b(F)(O) value that is in good agreement with experiment. A critical factor in any n-particle treatment is a balanced treatment of core and valence correlation. The size-extensive modified coupled-pair functional method provides b(F) values in reasonably good agreement with the FCI. Methods that account quantitatively for the valence correlation, such as complete-active-space self-consistent-field/multireference configuration interaction, appear to introduce an imbalance between core and valence contributions to b(F) when the one-particle basis sets are flexibly contracted in the core.}, keywords = {1ST-ROW HYDRIDES, basis sets, CI(SD), CONSTANTS, CONTRACTION, DIATOMIC-MOLECULES, EXCITED UPSILON-LESS-THAN-OR-EQUAL-TO-6 LEVELS, MANY-BODY CALCULATIONS, MICROWAVE-SPECTRUM, VALUES}, isbn = {0021-9606}, url = {://A1991FA77800045}, author = {Chong, D. P. and Langhoff, S. R. and Bauschlicher, C. W.} }