The Experts below are selected from a list of 234 Experts worldwide ranked by ideXlab platform
Gary E Douberly - One of the best experts on this subject based on the ideXlab platform.
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mid infrared signatures of hydroxyl containing water clusters infrared laser stark spectroscopy of oh h2o and oh d2o n n 1 3
Journal of Chemical Physics, 2015Co-Authors: Paul L Raston, Tao Liang, Federico J Hernandez, Joseph T Brice, Christopher M Leavitt, Gustavo A Pino, Gary E DouberlyAbstract:Small water clusters containing a single hydroxyl radical are synthesized in liquid helium droplets. The OH–H2O and OH(D2O)n clusters (n = 1-3) are probed with infrared laser spectroscopy in the vicinity of the hydroxyl radical OH stretch vibration. Experimental band origins are qualitatively consistent with ab initio calculations of the global minimum structures; however, frequency shifts from isolated OH are significantly over-predicted by both B3LYP and MP2 methods. An effective Hamiltonian that accounts for partial quenching of Electronic Angular Momentum is used to analyze Stark spectra of the OH–H2O and OH–D2O binary complexes, revealing a 3.70(5) D permanent electric dipole moment. Computations of the dipole moment are in good agreement with experiment when large-amplitude vibrational averaging is taken into account. Polarization spectroscopy is employed to characterize two vibrational bands assigned to OH(D2O)2, revealing two nearly isoenergetic cyclic isomers that differ in the orientation of the...
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on the stark effect in open shell complexes exhibiting partially quenched Electronic Angular Momentum infrared laser stark spectroscopy of oh c 2 h 2 oh c 2 h 4 and oh h 2 o
Journal of Molecular Spectroscopy, 2015Co-Authors: Christopher P Moradi, Gary E DouberlyAbstract:Abstract The Stark effect is considered for polyatomic open shell complexes that exhibit partially quenched Electronic Angular Momentum. Matrix elements of the Stark Hamiltonian represented in a parity conserving Hund’s case (a) basis are derived for the most general case, in which the permanent dipole moment has projections on all three inertial axes of the system. Transition intensities are derived, again for the most general case, in which the laser polarization has projections onto axes parallel and perpendicular to the Stark electric field, and the transition dipole moment vector is projected onto all three inertial axes in the molecular frame. Simulations derived from this model are compared to experimental rovibrational Stark spectra of OH–C 2 H 2 , OH–C 2 H 4 , and OH–H 2 O complexes formed in helium nanodroplets.
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infrared rovibrational spectroscopy of oh c2h2 in 4he nanodroplets parity splitting due to partially quenched Electronic Angular Momentum
Journal of Chemical Physics, 2015Co-Authors: Gary E Douberly, Paul L Raston, Tao Liang, Mark D MarshallAbstract:The T-shaped OH–C2H2 complex is formed in helium droplets via the sequential pick-up and solvation of the monomer fragments. Rovibrational spectra of the a-type OH stretch and b-type antisymmetric CH stretch vibrations contain resolved parity splitting that reveals the extent to which Electronic Angular Momentum of the OH moiety is quenched upon complex formation. The energy difference between the spin-orbit coupled 2B1 (A″) and 2B2 (A′) Electronic states is determined spectroscopically to be 216 cm−1 in helium droplets, which is 13 cm−1 larger than in the gas phase [Marshall et al., J. Chem. Phys. 121, 5845 (2004)]. The effect of the helium is rationalized as a difference in the solvation free energies of the two Electronic states. This interpretation is motivated by the separation between the Q(3/2) and R(3/2) transitions in the infrared spectrum of the helium-solvated 2Π3/2 OH radical. Despite the expectation of a reduced rotational constant, the observed Q(3/2) to R(3/2) splitting is larger than in th...
Alexander Dalgarno - One of the best experts on this subject based on the ideXlab platform.
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threshold laws for collisional reorientation of Electronic Angular Momentum
Physical Review A, 2003Co-Authors: Roman V Krems, Alexander DalgarnoAbstract:It is shown that the velocity dependence of cross sections for projection-changing transitions in collisions of paramagnetic atoms or molecules with structureless targets near threshold has the form v{sup 2{delta}}{sup m} when {delta}m is even and v{sup 2({delta}m+1)} when {delta}m is odd, where {delta}m is the change in the projection quantum number and v is the relative velocity.
E E Nikitin - One of the best experts on this subject based on the ideXlab platform.
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Semiclassical roronic description of right-left scattering asymmetry of helicopter-oriented atoms
Chemical Physics, 2001Co-Authors: E I Dashevskaya, R. Düren, E E NikitinAbstract:Abstract We present a semiclassical description of left-right scattering asymmetry of helicopter-oriented atoms on the basis of roronic correlation diagrams. The conservation of the total Angular Momentum and total parity is explicitly taken into account. The asymmetry is due to different populations of Electronic states of the diatom which is related to a non-sudden nature of the locking of the Electronic Angular Momentum to the rotating molecular axis. The theory is applied to measurements of differential cross sections for the scattering of oriented alkali atoms from rare gas atoms, and the experimental results are understood in a new light in terms of the basics of the interaction.
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computational study of the locking of Electronic Angular Momentum in diatomic quasimolecules
Journal of Physics B, 1993Co-Authors: A Berengolts, E I Dashevskaya, E E NikitinAbstract:A numerical study is performed for the locking of an Electronic Angular Momentum j=1 to the molecular axis during a collision of two atoms interacting via a potential proportional to an inverse power of the interatomic distance, R. Limitations to the notion of the locking radius and slipping probability are discussed in connection with the steepness of the interaction governed by the exponent n. Numerical calculations confirm the authors' earlier analytical result: the optimal criterion for determination of the locking radius is a condition for the accumulated phase difference between two molecular states. Analytical expressions are suggested for the locking angle and the slipping probability. The implication of the locking approximation for calculation of the quasiclassical scattering matrix is discussed.
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comparison equation approach to the locking of Electronic Angular Momentum to the molecular axis in atomic collisions
Journal of the Chemical Society Faraday Transactions, 1993Co-Authors: E I Dashevskaya, E E NikitinAbstract:A comparison equation is set up and solved for the locking of an Electronic Angular Momentum j= 1 to the molecular axis during a collision of two atoms. Two parameters which enter into the comparison equation characterize the strength and the abruptness of the locking. A solution found allows one to investigate the transition from loose locking to tight locking. A new definition of the locking distance is suggested. A method to calculate the slipping probability which describes the deviation of the locking event from its sudden limit is proposed.
Roman V Krems - One of the best experts on this subject based on the ideXlab platform.
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threshold laws for collisional reorientation of Electronic Angular Momentum
Physical Review A, 2003Co-Authors: Roman V Krems, Alexander DalgarnoAbstract:It is shown that the velocity dependence of cross sections for projection-changing transitions in collisions of paramagnetic atoms or molecules with structureless targets near threshold has the form v{sup 2{delta}}{sup m} when {delta}m is even and v{sup 2({delta}m+1)} when {delta}m is odd, where {delta}m is the change in the projection quantum number and v is the relative velocity.
Federico J Hernandez - One of the best experts on this subject based on the ideXlab platform.
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mid infrared signatures of hydroxyl containing water clusters infrared laser stark spectroscopy of oh h2o and oh d2o n n 1 3
Journal of Chemical Physics, 2015Co-Authors: Paul L Raston, Tao Liang, Federico J Hernandez, Joseph T Brice, Christopher M Leavitt, Gustavo A Pino, Gary E DouberlyAbstract:Small water clusters containing a single hydroxyl radical are synthesized in liquid helium droplets. The OH–H2O and OH(D2O)n clusters (n = 1-3) are probed with infrared laser spectroscopy in the vicinity of the hydroxyl radical OH stretch vibration. Experimental band origins are qualitatively consistent with ab initio calculations of the global minimum structures; however, frequency shifts from isolated OH are significantly over-predicted by both B3LYP and MP2 methods. An effective Hamiltonian that accounts for partial quenching of Electronic Angular Momentum is used to analyze Stark spectra of the OH–H2O and OH–D2O binary complexes, revealing a 3.70(5) D permanent electric dipole moment. Computations of the dipole moment are in good agreement with experiment when large-amplitude vibrational averaging is taken into account. Polarization spectroscopy is employed to characterize two vibrational bands assigned to OH(D2O)2, revealing two nearly isoenergetic cyclic isomers that differ in the orientation of the...