scholarly journals Vibrational Relaxation of XUV-Induced Hot Ground State Cations of Naphthalene

2021 ◽  
Author(s):  
Geert Reitsma ◽  
Serguei Patchkovskii ◽  
Judith Dura ◽  
Lorenz Drescher ◽  
Jochen Mikosch ◽  
...  
Keyword(s):  
Ground State ◽  
Vibrational Relaxation

scholarly journals Femtosecond Transient Absorption Studies of Simple Polyenes in Solution

1999 ◽  
Vol 19 (1-4) ◽  
pp. 371-374
Author(s):  
Kaoru Ohta ◽  
Yukito Naitoh ◽  
Keisuke Tominaga ◽  
Noboru Hirota ◽  
Keitaro Yoshihara
Keyword(s):  
Ground State ◽  
Vibrational Relaxation ◽  
Internal Conversion ◽  
Transient Absorption ◽  
Visible Region ◽  
Single Bond ◽  
Femtosecond Transient Absorption ◽  
Absorption Studies ◽  
Bond Proceeds ◽  
Subnanosecond Time

We have conducted femtosecond transient absorption experiments on the excited-state dynamics of trans- and cis-hexatriene (HT) in solution. The transient absorption in the visible region decays with the time constant of about 500 fs, indicating that the internal conversion (IC) to the ground state occurs quite efficiently. The bleach recovery signal contains several time constants. The vibrational relaxation in the ground state occurs in 10–20ps and the slow relaxation process, which may be due to the conformational change around C—C single bond, proceeds in a subnanosecond time scale.

THE DISSIPATIVE DOUBLE-WELL POTENTIAL: A MULTILEVEL SPIN HOPPING ANALYSIS

1991 ◽  
Vol 05 (05) ◽  
pp. 351-356
Author(s):  
H. DEKKER
Keyword(s):  
Energy Spectrum ◽  
Ground State ◽  
Vibrational Relaxation ◽  
Coupling Model ◽  
Quantum Mechanical ◽  
Time Dynamics ◽  
Novel Treatment ◽  
Model Hamiltonian ◽  
Double Well Potential ◽  
Ground State Doublet

A novel treatment is presented of the real-time dynamics of a quantum mechanical particle in a dissipative double-well potential at finite temperatures. The analysis is based on the bilinear coupling model Hamiltonian à la Zwanzig. The energy spectrum consists of a ladder of vibrational doublets. The usual truncation to the ground state doublet — à la Leggett et al. — is not required. The intra-doublet spin-boson dynamics is evaluated in the “noninteracting-blip approximation”. The inter-doublet vibrational relaxation gives rise to a stochastic hopping process.

The Master Equation for the Dissociation of a Dilute Diatomic Gas. XI. Vibrational Freezing in a Nozzle Flow

1974 ◽  
Vol 52 (6) ◽  
pp. 939-941 ◽  
Author(s):  
Nabil I. Labib ◽  
Huw O. Pritchard
Keyword(s):  
Relaxation Time ◽  
Energy Level ◽  
Master Equation ◽  
Rate Constant ◽  
Ground State ◽  
Vibrational Relaxation ◽  
Vibrational Energy ◽  
Nozzle Flow ◽  
Vibrational Energy Level ◽  
Diatomic Gas

A previously reported calculation on a model expansion in a nozzle flow is extended to the point where the whole vibrational energy "freezes" and the behavior of the vibrational relaxation time is examined. Starting with the high levels, each individual vibrational energy level becomes decoupled from the ground state in sequence, down to and including υ = 1; under these conditions, all measures of the vibrational relaxation time fail, but perhaps surprisingly the rate constant for recombination remains well defined.

Vacuum ultraviolet emission by active nitrogen. I. The formation and removal of N 2 (a 1 Π g )

1972 ◽  
Vol 330 (1580) ◽  
pp. 79-95 ◽  
Keyword(s):  
Ground State ◽  
Vibrational Relaxation ◽  
Emission Intensity ◽  
Vacuum Ultraviolet ◽  
Ultraviolet Emission ◽  
Active Nitrogen ◽  
Parallel Processes

The emission of the Lyman-Birge-Hopfield bands of N 2 (a 1 Π g ) - X 1 ∑ g + ), v ' ≤ 6 in active nitrogen is shown to originate from the recombination of ground state nitrogen atoms. Two parallel processes occur: ( а ) A two-body inverse predissociation populates rotational levels J > 13 of N 2 (a 1 Π g ), v ' = 6, from which there is rapid rotational and vibrational relaxation; this gives an emission intensity proportional to [N] 2 . ( b ) The reaction N( 4 S) + N 2 (B 3 Π g ) = N 2 (a 1 Π g ) + N( 4 S) (5) populates mainly lower levels of the a a 1 Π g state giving emission proportional to [N] 3 which is enhanced by argon carriers. Some measurements on N 2 (a' 1 ∑ u - ), v ' = 0 are also reported.

Vibrationally excited nitric oxide produced in the flash photolysis of nitrosyl halides

1962 ◽  
Vol 268 (1334) ◽  
pp. 291-303 ◽  
Keyword(s):  
Nitric Oxide ◽  
Energy Transfer ◽  
Ground State ◽  
Vibrational Relaxation ◽  
Direct Evidence ◽  
Flash Photolysis ◽  
Vibrational Energy ◽  
Electronic States ◽  
Vibrationally Excited ◽  
Direct Production

The flash photolysis of nitrosyl chloride and nitrosyl bromide has been studied under isothermal conditions. Vibrationally excited nitric oxide molecules were produced and all levels from v " = 0 to v " = 11 were observed in absorption from the ground electronic states in the β, γ, δ and Є systems. Some of these bands have not previously been reported. The mechanism of the production is either directly NO R + hv → NO ( X 2 II , v ≤ 11) + R ( 2 P ), or by the sequence which includes the reactions NO R + hv → NO( 4 II ) + R , NO. 4 II + M → NO ( X 2 II , v > 0) + M In the latter case, the 4 II state of NO lies not more than 3·5 eV above the ground state. Other possible mechanisms and models accounting for the direct production of vibrationally excited NO in its ground electronic states are discussed. By flashing chlorine in the presence of NOCl it was shown that the reaction Cl + NOCl → Cl 2 + NO ( v > 0) does not occur, thus providing direct evidence that in reactions of the type A + BCD → AB + CD only the AB molecule containing the newly formed bond can be vibrationally excited. Vibrational relaxation is very rapid and probably occurs by step-wise degradation involving resonance vibrational energy transfer. NOCl and NOBr are very efficient and with NO itself the reaction NO ( v = n ) + NO ( v = 0) → NO ( v = n -1) + NO ( v = 1) can be followed.

scholarly journals Фемтосекундная абсорбционная спектроскопия восстановленной и окисленной форм цитохром c оксидазы: возбужденные состояния и релаксационные процессы в гемовых центрах a и a-=SUB=-3-=/SUB=-

2019 ◽  
Vol 127 (10) ◽  
pp. 697
Author(s):  
И.В. Шелаев ◽  
Ф.Е. Гостев ◽  
Т.В. Выгодина ◽  
С.В. Лепешкевич ◽  
Б.М. Джагаров
Keyword(s):  
Cytochrome C ◽  
Excitation Energy ◽  
Cytochrome C Oxidase ◽  
Ground State ◽  
Vibrational Relaxation ◽  
Vibrational Energy ◽  
Relaxation Processes ◽  
Electronic Relaxation ◽  
Electronic Excitation Energy ◽  
Reduced Forms

AbstractExcited electronic states and intraheme relaxation processes in the oxidized and reduced forms of mitochondrial cytochrome c oxidase extracted from a beef heart have been investigated by femtosecond absorption spectroscopy. The spectral and kinetic characteristics of short-lived intermediates have been measured from 80 fs to 20 ps after the photoexcitation. It is found that nonradiative electronic relaxation of the excitation energy in heme a , both in the oxidized (Fe(III) a ) and reduced (Fe(II) a ) forms, occurs successively as three processes, after the end of which heme a is in the ground state with a large store of vibrational energy. The subsequent vibrational relaxation (heme cooling) lasts for several picoseconds. It is found for reduced heme a _3 (Fe(II) a _3) that the electronic relaxation occurs as a result of two successive stages, which changes to vibrational relaxation in the ground state. The mechanism and dynamics of electronic excitation energy conversion in cytochrome c oxidase are analyzed.

Renilla Bioluminescence: A Morphologic Approach to the Location of Photocytes

1974 ◽  
Vol 32 ◽  
pp. 208-209
Author(s):  
Ben O. Spurlock ◽  
Milton J. Cormier
Keyword(s):  
Excited State ◽  
Ground State ◽  
Molecular Basis ◽  
Light Emission ◽  
Chemical Basis ◽  
Electronic Excited State ◽  
Colonial Form ◽  
The Common ◽  
Eighteenth And Nineteenth Centuries ◽  
Catalyzed Oxidation

The phenomenon of bioluminescence has fascinated layman and scientist alike for many centuries. During the eighteenth and nineteenth centuries a number of observations were reported on the physiology of bioluminescence in Renilla, the common sea pansy. More recently biochemists have directed their attention to the molecular basis of luminosity in this colonial form. These studies have centered primarily on defining the chemical basis for bioluminescence and its control. It is now established that bioluminescence in Renilla arises due to the luciferase-catalyzed oxidation of luciferin. This results in the creation of a product (oxyluciferin) in an electronic excited state. The transition of oxyluciferin from its excited state to the ground state leads to light emission.

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