The Diatomics-in-Molecules Method and the Chemical Bond

Kuntz, P. J.

doi:10.1007/978-3-642-61277-0_9

Cited by 5 publications

(3 citation statements)

References 204 publications

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“…The diatomics-in-molecules method ͑DIM͒ is a semiempirical approach developed by Ellison [88][89][90] for computing potential energy surfaces ͑PES͒ of the ground and excited states of polyatomic systems from diatomic potentials. It is closely related to the semiempirical extended valence bond ͑EVB͒ methods 58,[91][92][93][94][95][96][97][98] and is ideally suitable for studies of the dynamics of a variety of chemical reactions.…”

Section: A Dim Methodsmentioning

confidence: 99%

Nonadiabatic molecular dynamics simulation of photodissociation and geminate recombination of I2 liquid xenon

Batista¹,

Coker²

1996

The Journal of Chemical Physics

129

113

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In this paper we investigate the B state predissociation and subsequent geminate recombination of photoexcited iodine in liquid xenon using a coupled quantum-classical molecular dynamics method and a model Hamiltonian gained from the diatomics-in-molecules semiempirical approach to excited state electronic structure including spin-orbit coupling. We explore the capabilities of these techniques as applied to studying the dynamics of realistic condensed phase reactions by comparing with available experimental data from recent ultrafast spectroscopic studies and Raman scattering measurements. We present a microscopic understanding of how the solvent perturbs the electronic states of the chromophore and opens various channels for dissociation from the bound excited B state. We survey the different possible dissociative channels and determine their relative importance as a function of solvent density. We find that predissociation usually occurs during the first bond extension within about 50-100 fs. We follow our trajectories out to 2 ps and observe early solvent collisions which, at the highest solvent densities studied, often result in geminate recombination to the excited bound AЈ state with in this time.

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Section: A Dim Methodsmentioning

confidence: 99%

Nonadiabatic molecular dynamics simulation of photodissociation and geminate recombination of I2 liquid xenon

Batista¹,

Coker²

1996

The Journal of Chemical Physics

129

113

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“…Invoking the zero overlap of atomic orbitals (ZOAO) approximation [23,24], these basis functions become:…”

Section: Dim and Diis Methodsmentioning

confidence: 99%

Ion pair state emission from I₂in rare gas matrices: effects of solvent induced symmetry breaking

Yu¹,

Coker²

2004

Molecular Physics

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In this paper, we employ a diabatic model Hamiltonian based on the DIM (diatomics-inmolecules) and DIIS (diatomics-in-ionic-systems) methods to describe the valence and ion-pair states of the iodine molecule, with the objective of characterizing the influence of Ar and Kr rare gas matrices on the ion-pair states. In particular, we combined this model Hamiltonian with classical simulations to calculate the shifts of the ion-pair state emission spectra due to solvation environment. The computed main emission peaks in Ar and Kr solids appear at 378 and 417 nm, in excellent agreement with the experimental emission peaks of 380 and 418 nm recently observed by Chergui et al. with the identical transition assignments. Our study also shows that these calculated bands correspond to redshifts from the gas phase of 2600 and 5100 cm À1 , compared with shifts of 2900 and 4700 cm À1 , respectively, observed in experiments, and the equilibrium bond lengths of the D 0 ð2 g Þ state in Ar and Kr extend to 3.70 and 3.75 Å compared to the gas-phase value of 3.594 Å , consistent with experimental implications. Emission bands originating from the ð2 u Þ state are also computed, as well as the counterparts of these bands in the visible region and the results are shown to be in reasonable agreement with experiments. We present a detailed study of the ion-pair state symmetry breaking which mixes the symmetrical gas-phase states resulting in charge localization, and the establishment of permanent molecular dipole moments in these solvated ion-pair state molecules due to local distortion of the polarizable matrix. Finally we use our calculations to explore model defect solvation sites in solid Ar which have been proposed as the source of various ambiguous emission bands in experimental spectra.

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“…Extensive examples, derivations, and applications can be found in the following articles and references therein. [11][12][13][16][17][18][19][20][21][22][23][24][25][26][27][28][29][30][31][32] The DIM Hamiltonian is an exact rewriting of the full electronic Schroedinger Hamiltonian, where Ĥ ij and Ĥ i are diatomic and monatomic operators. They are defined so that they apply only to the electrons originally assigned to atom i and atom j, respectively.…”

Section: Methodsmentioning

confidence: 99%

A New Semiempirical Approach to Study Ground and Excited States of Metal Complexes in Biological Systems

et al. 2002

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In this paper we develop a "diatomic in molecules semiempirical ligand field" (DIMSELF) method to calculate ground and excited many-body potential energy surfaces for an arbitrary transition metal ion in an arbitrary complex system. This method is not restricted to a high-symmetry environment and is meant to be inexpensive and suitable for nonadiabatic excited states dynamics on-the-fly. Within the approximations employed, the method includes full CI (configuration interaction) and SO (spin-orbit) interactions, essential to the description of nonradiative transitions such as those of myoglobin in the presence of carbon monoxide. We test our method against high level ab initio calculations for a simple model system of myoglobin's heme pocket. Finally, we discuss our results and compare with previous calculations in the literature.

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The Diatomics-in-Molecules Method and the Chemical Bond

Cited by 5 publications

References 204 publications

Nonadiabatic molecular dynamics simulation of photodissociation and geminate recombination of I2 liquid xenon

Nonadiabatic molecular dynamics simulation of photodissociation and geminate recombination of I2 liquid xenon

Ion pair state emission from I₂in rare gas matrices: effects of solvent induced symmetry breaking

A New Semiempirical Approach to Study Ground and Excited States of Metal Complexes in Biological Systems

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The Diatomics-in-Molecules Method and the Chemical Bond

Cited by 5 publications

References 204 publications

Nonadiabatic molecular dynamics simulation of photodissociation and geminate recombination of I2 liquid xenon

Nonadiabatic molecular dynamics simulation of photodissociation and geminate recombination of I2 liquid xenon

Ion pair state emission from I2in rare gas matrices: effects of solvent induced symmetry breaking

A New Semiempirical Approach to Study Ground and Excited States of Metal Complexes in Biological Systems

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Ion pair state emission from I₂in rare gas matrices: effects of solvent induced symmetry breaking