Nature of the Methanol-Methyl Borate Azeotrope

Tully, Thomas J.; Christopher, Phoebus M.

doi:10.1021/j150557a033

Cited by 33 publications

(58 citation statements)

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“…But the conversion will eventually take place, because the chemisorption well for the triplet O 2 is quite deep, and once chemisorbed, the O 2 molecule is unlikely to escape. In such a situation, the Landau-Zener-Stueckelberg formula does not apply, as the trapped O 2 goes through molecular vibration and passes through the crossing points between the triplet and singlet potential surfaces many times [19][20][21]. From this perspective, the spin conversion from the triplet to the singlet state is not the bottleneck that narrows down the chemisorption channel, as previously suggested [13].…”

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confidence: 90%

“…If a triplet O 2 can be trapped on Si(100) by chemisorption, it can pass through the crossing point many times and the conversion probability is greatly enhanced. Such a model of trapping enhanced spin conversion was first illustrated by Tully [19], and Miller and co-workers [20] in the collisional quenching of O 1 D by N 2 , and recently applied to the spinforbidden reactions in organometallic complexes [21].…”

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Adsorption of TripletO2on Si(100): The Crucial Step in the Initial Oxidation of a Silicon Surface

et al. 2005

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It has long been understood that a precursor mediated chemisorption is a significant part of the dynamics for the adsorption of O(2) on Si(100), which is a much studied model system of surface reaction with considerable technological relevance. However, theoretical studies on the interaction between O(2) and Si(100) have been focused on the excited singlet state of O2 and unable to explain the observations in surface scattering experiments. We demonstrate by first principles calculations that such a focus is misplaced. In reality, triplet O(2) can also react with Si(100), after overcoming small barriers, and its reaction paths provide a full account for experiments. Our results highlight the important role played by triplet O(2) in surface oxidation.

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confidence: 90%

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confidence: 99%

Adsorption of TripletO2on Si(100): The Crucial Step in the Initial Oxidation of a Silicon Surface

et al. 2005

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“…The involvement of a CO 2 quasibound complex in the IB2 state is assumed in the quenching ofO( ID) atoms by CO molecules. 28 The Doppler profiles involving different J states of the CO product are characterized by an anisotropy parameter of fJ = O. Since the CO 2 absorption spectrum near 157 nm is broadened enough so that the rotational structure is unresolved, it is certain that the initially excited state has a short enough lifetime so that rotational motion cannot account for the reduction in anisotropy from the expected values of fJ = 2.0 or fJ = -1.0 for parallel or perpendicular transitions, respectively, in the linear molecule.…”

Section: The Dissociation Mechanismmentioning

confidence: 99%

Product distributions in the 157 nm photodissociation of CO2

Miller

Kable

Houston

et al. 1992

The Journal of Chemical Physics

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The vibrational and rotational distributions of CO ( I ~g+ ) produced in the 157 nm photodissociation of CO 2 have been determined by measuring vacuum-ultraviolet laserinduced fluorescence spectra of the co photoproduct. The photodissociation of CO 2 is known to occur via two pathways; one yielding 0 ( I D) and the other yielding 0 e P). Spin conservation and previous experimental studies confirm that dissociation via the O( ID) channel is the dominant process. The available energy for this channel is sufficient to populate only the ground and first excited vibrational levels of CO. We measured the rotational distributions for CO in v = 0 and v = 1 and found them to be nonBoltzmann. In fact, a highly structured distribution with distinct peaks at J = 10, 24, 32, and 39 is observed for CO in v = O. A less structured population is displayed by molecules in v = 1. The relative vibrational population (v = O/v = 1) was determined to be 3.7 ± 1.2. Doppler spectra of individual rovibronic transitions were also recorded. The profiles have widths in accord with the available translational energy, display the expected v IJ correlation, and are best described by an isotropic distribution of the velocity vectors with respect to the polarization direction of the dissociation light.

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“…In this review, we discuss the nonadiabatic transition state theory (NA‐TST), one of the time‐independent statistical approaches to calculating the rates of intersystem crossings . Some other statistical methods for calculating intersystem crossing rates, including Fermi's golden rule and Condon approximations, have been reviewed recently .…”

Section: Introductionmentioning

confidence: 99%

Nonadiabatic transition state theory: Application to intersystem crossings in the active sites of metal‐sulfur proteins

Lykhin

Kaliakin

dePolo

et al. 2016

Int J of Quantum Chemistry

139

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Nonadiabatic transition state theory (NA-TST) is a powerful tool to investigate the nonradiative transitions between electronic states with different spin multiplicities. The statistical nature of NA-TST provides an elegant and computationally inexpensive way to calculate the rate constants for intersystem crossings, spin-forbidden reactions, and spin-crossovers in large complex systems. The relations between the microcanonical and canonical versions of NA-TST and the traditional transition state theory are shown, followed by a review of the basic steps in a typical NA-TST rate constant calculation. These steps include evaluations of the transition probability and coupling between electronic states with different spin multiplicities, a search for the minimum energy crossing point (MECP), and computing the densities of states and partition functions for the reactant and MECP structures. The shortcomings of the spin-diabatic version of NA-TST related to ill-defined state coupling and state counting are highlighted. In three examples, we demonstrate the application of NA-TST to intersystem crossings in the active sites of metal-sulfur proteins focusing on [NiFe]-hydrogenase, rubredoxin, and Fe 2 S 2 -ferredoxin.

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Nature of the Methanol-Methyl Borate Azeotrope

Cited by 33 publications

References 2 publications

Adsorption of TripletO2on Si(100): The Crucial Step in the Initial Oxidation of a Silicon Surface

Adsorption of TripletO2on Si(100): The Crucial Step in the Initial Oxidation of a Silicon Surface

Product distributions in the 157 nm photodissociation of CO2

Nonadiabatic transition state theory: Application to intersystem crossings in the active sites of metal‐sulfur proteins

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