Experimental Observations Regarding Transition States

Brooks, Ph. R.; Curl, R. F.; Maguire, T. C.

doi:10.1002/bbpc.19820860513

Cited by 55 publications

(8 citation statements)

References 24 publications

(2 reference statements)

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“…Brooks et al used laser excitation during reactive collisions to study the transition states of chemical reactions (117). In their study, a nanosecond laser, not resonant with the asymptotic transitions of reactants or products, was used to open a chemiluminescent product channel; this was perhaps one of the first attempts to change the course of a bimolecular reaction by excitation of the transient collision complex.…”

Section: Free-bound Bimolecular Reactions: Photoassociationmentioning

confidence: 99%

COHERENTNONLINEARSPECTROSCOPY: From Femtosecond Dynamics to Control

Dantus

2001

Annu. Rev. Phys. Chem.

118

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This review focuses on the study of the dynamics of isolated molecules and their control using coherent nonlinear spectroscopic methods. Emphasis is placed on topics such as bound-to-free excitation and the study of concerted elimination reactions, free-to-bound excitation and the study of bimolecular reactions, and bound-to-bound excitation and the study of intramolecular rovibrational dynamics and coherence relaxation. For each case the detailed time-resolved information reveals possible strategies to control the outcome. Experimental results are shown for each of the reactions discussed. The methods discussed include pump-probe and four-wave mixing processes such as transient grating and photon echo spectroscopy. Off-resonance transient-grating experiments are shown to be ideal for the study of ground state dynamics, molecular structure, and the molecular response to strong field excitation.

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Section: Free-bound Bimolecular Reactions: Photoassociationmentioning

confidence: 99%

COHERENTNONLINEARSPECTROSCOPY: From Femtosecond Dynamics to Control

Dantus

2001

Annu. Rev. Phys. Chem.

118

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“…A wealth of information about the {Hg-H2] system was obtained from the experimental data, which consisted of (1) measurements of total fluorescence vs UV wavelength (fluorescence excitation spectra), (2) fluorescence of a specific quantum state vs UV wavelength (action spectra), and (3) fluorescence measurements as the probe laser is scanned at fixed UV wavelength (product spectra). Interpretation of these data suggests that reaction to form HgH from the II state is direct (=0.1 ps) since the action spectrum is continuous, whereas reaction from the S state is indirect since rovibrational structure is observed.…”

Section: Photon-assisted Bimolecular Reactionsmentioning

confidence: 99%

“…Absorption in the Na + Ar collision system occurs in one of two ways: (1) If the atoms approach on the curve marked "Lx" in Figure 22b, adiabatically traverse the crossing region at rc to curve "L2", and then make a nonadiabatic traversal of the crossing on the way out, they will end up on curve "Ux" corresponding to Na* + Ar. (2) If the atoms jump to "U2" on the way in and then make an adiabatic transition on the way out, they also end up on curve "Ux", corresponding to Na* + Ar. In either case, one jump and one adiabatic transition produce excited products.…”

Section: Dressed Statesmentioning

confidence: 99%

Spectroscopy of transition region species

Brooks¹

1988

Chem. Rev.

114

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Contents I. Introduction 407 A. Scope of Review 408 II. Overview 408 III. Background 409 A, One-Species Transitions 409 1. Forbidden Transitions 409 2. Line Broadening (Allowed Transitions) 409 3. The Quasi-Static Theory (QST) 410 4. Collisional Redistribution 411 B. Two-Species Transitions 411 IV. Chemical Reactions (Multiple-Species 412 Transitions) A. Absorption 412 1. Photon-Assisted Association 412 2. Photon-Assisted Associative Ionization 414 3. Photon-Assisted Bimolecular Reactions 415 B. Emission 419 1. Activation by Chemical Reaction 419 2. Activation by Photodissociation 419 V. van der Waals Molecules vs Transition Region 421 Species A. Location on the Surface 421 B. Transience vs Equilibrium 421 VI. Theory and Interpretation 422 A. Transitions between Two Levels 422 B. Electronic Transitions 423 1. Potential Energy Curves 423 2. Dressed States 424 3. Potential Energy Surfaces 424 VII. Conclusions 425 VIII. A Postscript 426 IX. Acknowledgments 426During a chemical reaction event, old bonds dissolve and new bonds form. Transient species are formed that are neither reagents nor products, but instead are species in transition between reagents and products. The nature and time evolution of these transient species obviously carry an enormous amount of information about the chemical reaction. This article reviews methods being devised to spectroscopically probe these species.

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“…Curiously, discussion of the possibilities for spectroscopy of transition states has not until now encompassed the case of the most fundamental of chemical exchange reactions, H+H2 H H2+H (1) + (here H is (12S) and H2 is Xg i.e., both are in their electronic ground states).…”

Section: Computed Absorption Spectra For Himentioning

confidence: 99%

The Spectroscopy of Transition States in H+H₂ Reaction, and NaI Photodissociation

et al. 1983

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(a). We have computed an approximate absorption spectrum for unstable intermediates H3≠ which constitute the transition states in the fundamental exchange reaction H+H2→H3≠→H2+H. Reaction takes place across the Siegbahn, Liu, Truhlar, Horowitz (SLTH) ground state energy surface, and electronic excitation is to the bound state that correlates with H*(22P)+H2. Features in the spectrum are indicative of the favored turning points for the mean of many classical trajectories across the SLTH surface. (b). Preliminary experimental data are reported which give evidence of emission arising from the transition states of NaI≠* in the (cw or pulsed) photolysis of NaI→222nmNaI≠*→Na*(32P)+I. The observed transition state emission is compared with a simple calculation.

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Experimental Observations Regarding Transition States

Cited by 55 publications

References 24 publications

COHERENTNONLINEARSPECTROSCOPY: From Femtosecond Dynamics to Control

COHERENTNONLINEARSPECTROSCOPY: From Femtosecond Dynamics to Control

Spectroscopy of transition region species

The Spectroscopy of Transition States in H+H₂ Reaction, and NaI Photodissociation

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Experimental Observations Regarding Transition States

Cited by 55 publications

References 24 publications

COHERENTNONLINEARSPECTROSCOPY: From Femtosecond Dynamics to Control

COHERENTNONLINEARSPECTROSCOPY: From Femtosecond Dynamics to Control

Spectroscopy of transition region species

The Spectroscopy of Transition States in H+H2 Reaction, and NaI Photodissociation

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Product

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The Spectroscopy of Transition States in H+H₂ Reaction, and NaI Photodissociation