Microwave spectrum of the OD–OH2 complex: A strong deuterium isotope effect on angular momentum quenching in the hydroxyl moiety

Wu, Steven S.; Sedo, Galen; Leopold, K. R.

doi:10.1016/j.jms.2008.09.012

Cited by 11 publications

(12 citation statements)

References 37 publications

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“…8 These two electronic states are differentiated by the orientation of the half-filled pπ orbital localized on the hydroxyl radical, which lies either in the symmetry plane ( 2 A ′ ) or perpendicular to it ( 2 A ′′ ). Experimental results confirm the global minimum structure predicted ab initio, 10,13,14,16,[21][22][23]46,47 with the most convincing characterization coming from the microwave (MW) measurements of Endo and co-workers 16 and Leopold, Marshall, and coworkers. 21,46,47 Francisco and coworkers examined the OH-H 2 O global interaction potential and found an A ′′ to A ′ state crossing along a path that interconverts isomers 1a and 1b, suggesting further investigations into the effect of this low-energy excited state on the reactivity of OH in the presence of water.…”

Section: Introductionsupporting

confidence: 74%

“…21,46 Microwave spectroscopy of gas-phase OH-H 2 O confirms via hyperfine splitting that the 2 A ′ electronic state is the global minimum. 21,46,47 Partial quenching of orbital angular momentum upon complex formation leads to parity doubling of rotational levels, 71,72 the extent of which reveals the energetic separation between 2 A ′ and 2 A ′′ states. 21,46,47 In the absence of spin-orbit coupling, the 2 A ′′ state is located 146.56 cm −1 above the 2 A ′ ground state.…”

Section: Oh-h(d) 2 Omentioning

confidence: 99%

“…1,2,36 Overview perspectives of the catalytic properties of water and its impact on tropospheric chemistry can be found in Refs. 35 and 36. As a result of several theoretical and experimental studies, 7,8,[21][22][23]46,47 the structure of the OH-H 2 O radical is widely accepted. With ab initio computations, two hydrogenbonded structures were discovered in which the hydroxyl radical acts as either the hydrogen bond donor (1a) or acceptor (1b).…”

Section: Introductionmentioning

confidence: 99%

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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)

Hernández

Brice

Leavitt

et al. 2015

The Journal of Chemical Physics

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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 non-hydrogen-bonded deuterium atoms relative to the plane of the three oxygen atoms. The dipole moments for these clusters are determined to be approximately 2.5 and 1.8 D for "up-up" and "up-down" structures, respectively. Hydroxyl stretching bands of larger clusters containing three or more D2O molecules are observed shifted approximately 300 cm(-1) to the red of the isolated OH radical. Pressure dependence studies and ab initio calculations imply the presence of multiple cyclic isomers of OH(D2O)3.

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Section: Introductionsupporting

confidence: 74%

Section: Oh-h(d) 2 Omentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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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)

Hernández

Brice

Leavitt

et al. 2015

The Journal of Chemical Physics

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“…(i) Binary van der Waals complexes of a diatomic free radical (e.g., NO, OH) in a 2 Π state with an inert gas atom or a closed-shell molecule. [9][10][11][12][13][14][15][16][17][18] The ground state of the free radical has two separate SO components, 2 1/2 Π and 2 3/2 Π . Interaction between the two monomers lifts the degeneracy of the x π and y π orbitals of the free radical, which leads to a barrier to free orbital motion and to a quenching of the orbital angular momentum of the unpaired electron.…”

Section: Introductionmentioning

confidence: 99%

Rotational and fine structure of open-shell molecules in nearly degenerate electronic states

Liu

2018

The Journal of Chemical Physics

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An effective Hamiltonian without symmetry restriction has been developed to model the rotational and fine structure of two nearly degenerate electronic states of an open-shell molecule. In addition to the rotational Hamiltonian for an asymmetric top, this spectroscopic model includes the energy separation between the two states due to difference potential and zero-point energy difference, as well as the spin-orbit (SO), Coriolis, and electron spin-molecular rotation (SR) interactions. Hamiltonian matrices are computed using orbitally and fully symmetrized case (a) and case (b) basis sets. Intensity formulae and selection rules for rotational transitions between a pair of nearly degenerate states and a nondegenerate state have also been derived using all four basis sets. It is demonstrated using real examples of free radicals that the fine structure of a single electronic state can be simulated with either a SR tensor or a combination of SO and Coriolis constants. The related molecular constants can be determined precisely only when all interacting levels are simulated simultaneously. The present study suggests that analysis of rotational and fine structure can provide quantitative insights into vibronic interactions and related effects.

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“…However, as the strength of the intermolecular interaction increases, the electronic angular momentum becomes partially quenched due to the incipient barrier to free orbital motion of the electron about the OH axis. A zero-field model Hamiltonian and simulated spectra for these systems have been reported by Marshall and Lester [20,21], and their model has been applied successfully to interpret the rovibrational infrared (IR) spectra of the T-shaped OH-C 2 H 2 complex [22,23] and the microwave spectra of the OH-H 2 O complex [24][25][26]. Using a model Hamiltonian adapted from this previous zero-field work, simulations are shown to be in excellent agreement with the Stark spectra of the OH-C 2 H 2 , OH-C 2 H 4 , and OH-H 2 O complexes formed in helium nanodroplets.…”

Section: Introductionmentioning

confidence: 99%

On the Stark effect in open shell complexes exhibiting partially quenched electronic angular momentum: Infrared laser Stark spectroscopy of OH–C2H2, OH–C2H4, and OH–H2O

Moradi

Douberly

2015

Journal of Molecular Spectroscopy

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a b s t r a c tThe 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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Microwave spectrum of the OD–OH2 complex: A strong deuterium isotope effect on angular momentum quenching in the hydroxyl moiety

Cited by 11 publications

References 37 publications

Mid-infrared signatures of hydroxyl containing water clusters: Infrared laser Stark spectroscopy of OH–H2O and OH(D2O)n (n = 1-3)

Mid-infrared signatures of hydroxyl containing water clusters: Infrared laser Stark spectroscopy of OH–H2O and OH(D2O)n (n = 1-3)

Rotational and fine structure of open-shell molecules in nearly degenerate electronic states

On the Stark effect in open shell complexes exhibiting partially quenched electronic angular momentum: Infrared laser Stark spectroscopy of OH–C2H2, OH–C2H4, and OH–H2O

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