scholarly journals Femtochemistry of bimolecular reactions from weakly bound complexes: computational study of the H + H'OD → H'OH + D / HOD + H' exchange reactions

2021 ◽  
Author(s):  
Alexandre P. Voute ◽  
Fabien Gatti ◽  
Klaus Braagaard Møller ◽  
Niels Engholm Henriksen
Keyword(s):  
Computational Study ◽  
Exchange Reactions ◽  
Weakly Bound ◽  
Bimolecular Reactions ◽  
Weakly Bound Complexes ◽  
Hydrogen Bound ◽  
Wavepacket Propagation

A full-dimensional wavepacket propagation describing the bimolecular exchange reactions H + H'OD → H'OH + D / HOD + H' initiated by photolysis of HCl in the hydrogen-bound complex (HCl)···(HOD)...

Dynamics of Ground State Bimolecular Reactions

1996 ◽  
Author(s):  
Curt Wittig ◽  
Ahmed H. Zewail
Keyword(s):  
Ground State ◽  
State Level ◽  
Chemical Transformations ◽  
Weakly Bound ◽  
Bimolecular Reactions ◽  
Weakly Bound Complexes ◽  
Electronically Excited ◽  
Gaseous Media ◽  
Chemical Selectivity ◽  
Elementary Chemical

During the past decade, the study of photoinitiated reactive and inelastic processes within weakly bound gaseous complexes has evolved into an active area of research in the field of chemical physics. Such specialized microscopic environments offer a number of unique opportunities which enable scientists to examine regiospecific interactions at a level of detail and precision that invites rigorous comparisons between experiment and theory. Specifically, many issues that lie at the heart of physical chemistry, such as reaction probabilities, chemical branching ratios, rates and dynamics of elementary chemical processes, curve crossings, caging, recombination, vibrational redistribution and predissociation, etc., can be studied at the state-to-state level and in real time. Inevitably, understanding the photophysics and photochemistry of weakly bound complexes lends insight into corresponding processes in less rarefied surroundings, for example, molecules physisorbed on crystalline insulator and metal surfaces, molecules residing on the surfaces of various ices, and molecules weakly solvated in liquids. However, such ties to the real world are not the main driving force behind studies of photoinitiated reactions in complexed gaseous media. Rather, it is the lure of going a step beyond the more common molecular environments. Theoretical modeling, which in many areas purports to challenge experiment, must rise to the occasion here if it is to offer predictive capability for even the simplest of such microcosms. Subtleties abound. Roughly speaking, two disparate regimes can be identified which are accessible experimentally and which correspond to qualitatively different kinds of chemical transformations. These are distinguished by their reactants: electronically excited versus ground state. For example, it is possible to study the chemical selectivity that derives from the alignment and orientation of excited electronic orbitals, albeit at restricted sets of nuclear coordinates. This is achieved by electronically exciting a complexed moiety, such as a metal atom, which then undergoes chemical transformations that depend on the geometric properties of the electronic orbitals such as their alignments and orientations relative to the other moiety (or moieties) in the complex.

scholarly journals Modelling excited states of weakly bound complexes with density functional theory

2014 ◽  
Vol 16 (28) ◽  
pp. 14455-14462 ◽  
Author(s):  
Edward A. Briggs ◽  
Nicholas A. Besley
Keyword(s):  
Density Functional Theory ◽  
Excited States ◽  
Density Functional ◽  
Rydberg State ◽  
Dispersion Correction ◽  
Weakly Bound ◽  
Functional Theory ◽  
Weakly Bound Complexes

Different dispersion correction parameters are required to describe the interaction when the molecule is in an excited Rydberg state.

Unimolecular processes in weakly bound complexes: correlated product state distributions

1995 ◽  
Vol 102 ◽  
pp. 323 ◽  
Author(s):  
L. Oudejans ◽  
R. E. Miller ◽  
W. L. Hase
Keyword(s):  
Product State ◽  
Weakly Bound ◽  
Weakly Bound Complexes

The structure and harmonic vibrational frequencies of the weakly bound complexes formed by HF with CO, CO2 and N2O

1988 ◽  
Vol 74 (5) ◽  
pp. 415-428 ◽  
Author(s):  
Ian L. Alberts ◽  
Nicholas C. Handy ◽  
Emmanuel D. Simandiras
Keyword(s):  
Vibrational Frequencies ◽  
Weakly Bound ◽  
Weakly Bound Complexes

Density functional theory (DFT) calculations on the structures and stabilities of [CnO2n+1]2– and [CnO2n+1]X2 polycarbonates containing chainlike (CO2)n units (n = 2–6; X = H or Li)

2011 ◽  
Vol 89 (6) ◽  
pp. 671-687 ◽  
Author(s):  
Pablo J. Bruna ◽  
Friedrich Grein ◽  
Jack Passmore
Keyword(s):  
Density Functional Theory ◽  
Density Functional ◽  
Ion Pairs ◽  
Dicarboxylic Acids ◽  
Polarizable Continuum Model ◽  
Weakly Bound ◽  
Functional Theory ◽  
The Density Functional Theory ◽  
Weakly Bound Complexes

The structures and stabilities of chainlike (CO2)n (n = 2–6) polycarbonates, where adjacent C atoms are linked by C–O–C bonds, were investigated at the density functional theory (DFT) level (B3PW91/6–311G(2d,p)), including dicarboxylic dianions, [CnO2n+1]2–, and the corresponding acids, [CnO2n+1]H2, and Li salts, [CnO2n+1]Li2. At equilibrium, the most stable systems have Cs, C2, or C2v symmetries. In the gas phase, these dianions are generally metastable with respect to spontaneous ejection of one electron, yet in the presence of counterions they become stabilized, for example, as [CnO2n+1]2–(Li+)2 ion pairs. [CnO2n+1]2– linkages are also stabilized as dicarboxylic acids, [CnO2n+1]H2; we find the latter to have equilibrium conformations of higher symmetry than previously reported in the literature. To the best of our knowledge, none of the [CnO2n+1]X2 (X = Li or H) compounds with n ≥ 2 have been reported in the experimental literature (albeit, the alkyl esters C2O5R2 and C3O7R2 are commercially available). All CO bonds in C2O5X2 to C6O13X2 have single- to double-bond character (≈140–118 pm), indicating that the [CnO2n+1] moieties are held together by strong chemical forces (in contrast to the weakly bound complexes (CO2)n and (CO2)n–, n > 1). Vibrational frequencies were calculated to ensure all conformations were true minima. The IR and Raman intensities show that the high intensity C=O stretching modes (1750 ± 100 cm–1) will help in the spectral characterization of these compounds. Solvation calculations using the polarizable continuum model (PCM) find that C2O52– can be formed via CO32– + CO2 as well as CO3–[Formula: see text], each reaction having ΔG298 < 0 in practically all solvents. This result confirms the experimentally observed large solubility of CO2(g) in molten carbonates, CO3M2 (M = Li, Na, or K). In contrast, starting with n = 2, the reactions [CnO2n+1]2– + CO2 do not proceed spontaneously in any solvent (ΔG298 > 0).

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