Single vibronic level fluorescence spectra from Ã (1B2u) benzene: Fermi resonances and S0 IVR lifetimes

Nicholson, Joanne A.; Lawrence, Warren D.; Fischer, Gad

doi:10.1016/0301-0104(95)00058-v

Cited by 16 publications

(20 citation statements)

References 56 publications

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“…Our fluorescence emission spectra of benzene (Figure ) possessed vibrational progressions that are in agreement with those found in the literature. ,− , The first mode of the vibrational progression in the ground state was clearly apparent in the emission spectrum. This vibrational mode dominates in the emission of gas-phase benzene, as well as in neat benzene or benzene in an ice matrix, both at 20 K . This is in contrast with the reported data by Donaldson and co-workers, who presented an emission spectrum possessing multiple unassigned bands, which are characteristic neither for benzene nor its excimers …”

Section: Discussioncontrasting

confidence: 89%

“…83,[89][90][91]104 The first mode of the vibrational progression in the ground state was clearly apparent in the emission spectrum. This vibrational mode dominates in the emission of gas-phase benzene, 105 as well as in neat benzene or benzene in an ice matrix, both at 20 K. 104 This is in contrast with the reported data by Donaldson and co-workers, who presented an emission spectrum possessing multiple unassigned bands, which are characteristic neither for benzene nor its excimers. 14 The emission spectra of benzene dimers and excimers have already been obtained under conditions of supersonic beam expansion (low vibrational excitation).…”

Section: ■ Results and Discussionmentioning

confidence: 99%

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Spectroscopic Properties of Benzene at the Air–Ice Interface: A Combined Experimental–Computational Approach

et al. 2014

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A combined experimental and computational approach was used to study the spectroscopic properties of benzene at the ice-air interface at 253 and 77 K in comparison with its spectroscopic behavior in aqueous solutions. Benzene-contaminated ice samples were prepared either by shock-freezing of benzene aqueous solutions or by benzene vapor-deposition on pure ice grains and examined using UV diffuse reflectance and emission spectroscopies. Neither the absorption nor excitation nor emission spectra provided unambiguous evidence of benzene associates on the ice surface even at a higher surface coverage. Only a small increase in the fluorescence intensity in the region above 290 nm found experimentally might be associated with formation of benzene excimers perturbed by the interaction with the ice surface as shown by ADC(2) excited-state calculations. The benzene associates were found by MD simulations and ground-state DFT calculations, although not in the arrangement that corresponds to the excimer structures. Our experimental results clearly demonstrated that the energy of the S0 → S1 electronic transition of benzene is not markedly affected by the phase change or the microenvironment at the ice-air interface and its absorption is limited to the wavelengths below 268 nm. Neither benzene interactions with the water molecules of ice nor the formation of dimers and microcrystals at the air-ice interface thus causes any substantial bathochromic shift in its absorption spectrum. Such a critical evaluation of the photophysical properties of organic contaminants of snow and ice is essential for predictions and modeling of chemical processes occurring in polar regions.

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Section: Discussioncontrasting

confidence: 89%

Section: ■ Results and Discussionmentioning

confidence: 99%

Spectroscopic Properties of Benzene at the Air–Ice Interface: A Combined Experimental–Computational Approach

et al. 2014

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“…Considering that minimal information is required to use Eq. (16), and that no fitting parameter is involved, the agreement is remarkable.…”

Section: Population Diffusion and Equipartition In Quantum Systems Ofmentioning

confidence: 80%

“…(16) with experiments is shown in Table I. T r is related to g, the measured half-widthat-half-maximum of the resonance spectrum, by 1͞T r 4pg.…”

Section: Population Diffusion and Equipartition In Quantum Systems Ofmentioning

confidence: 99%

Population Diffusion and Equipartition in Quantum Systems of Many Degrees of Freedom

Tsaur

Wang

1998

Phys. Rev. Lett.

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In the interaction picture, population transfer among coupled degrees of freedom is greatly enhanced by resonances. We show that statistically the number of resonances increases rapidly with degrees of freedom, changing the characteristic of population transfer from being bounded to diffusive. From the diffusion rate we derive simple expressions for the time scales of energy relaxation and equipartition. These expressions are supported by a wide range of experimental data. The analysis elucidates quantitatively the dependence of equipartition on resonances. [S0031-9007(98)05893-1] PACS numbers: 05.30.Ch, 31.70.Hq, 82.20.Rp Linearity is one of the most amazing features of quantum mechanics. The spectral decomposition theorem guarantees the existence of a complete orthogonal set of energy eigenstates. In the representation of energy eigenstates, populations of states do not change with time; hence population transfer among genuine eigenstates simply does not occur. However, in practice more often the wave functions of eigenstates are too difficult to solve or use. Therefore, nontrivial quantum dynamic systems are mostly described in the so-called interaction picture, in which the Hamiltonian is decomposed into a solvable major partĤ 0 and a minor perturbative partV . In the interaction picture the physical system is represented by eigenstates ofĤ 0 , which are coupled to each other bŷ V . In this picture the population changes with time. If H 0 consists of individually solvable parts representing different degrees of freedom, the population change is interpreted as energy transfer among degrees of freedom.Energy transfer among a group of coupled states is greatly enhanced when they satisfy the resonance condition n ? E ϵ "Dv ഠ 0, where n ͑n 1 , n 2 , . . .͒ is a nonzero integer array, E ͑E 1 , E 2 , . . .͒ is the energy of the coupled states, and Dv is the resonance detuning. For a simple system near the ground state, the number of involved energy levels is small, the resonance condition is satisfied only by accident. But in systems of many degrees of freedom where the number of such combinations is large, it would not be a surprise to find many resonances. In this case it is nearly impossible to track the population flow of individual states. Instead, a statistical description of the process is more useful.Energy transfer in quantum systems has been treated with various models and methods [1]. In many works the general emphasis has been greater on the nonlinear dynamics than on statistical average. Thus, these methods rely heavily on numerical computation to go beyond the mathematical formalism. On the other hand, in a series of recent papers Wolynes, Leitner, and Logan have brought novel approaches to the problem. By modeling multidimensional quantum systems with Cayley trees and analyzing their connectivity with self-consistent solutions of the renormalized Feenberg perturbation series, the authors have addressed important questions such as criterion of quantum ergodicity [2][3][4][5], energy relaxation rates...

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“…Single vibronic level (SVL) fluorescence spectra have been extensively studied to obtain information about the process of intramolecular vibrational energy redistribution (IVR) − and internal conversion (IC) of excited states. − In a SVL experiment (Scheme a), a vibrationally excited state is populated by laser excitation (blue arrow) with a well-defined frequency that matches the energy difference between the zero-point level in the electronic ground state (S 0 ) and the vibrationally excited level in the electronically excited state (S 1 ). After excitation, emission occurs from the populated vibronic level only (red arrows).…”

mentioning

confidence: 99%

Generating Function Approach to Single Vibronic Level Fluorescence Spectra

Tapavicza

2019

J. Phys. Chem. Lett.

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An efficient time-dependent generating function method to compute vibronic emission and absorption spectra arising from transitions from a singly excited vibrational initial state is presented. In contrast to existing finite temperature approaches that intrinsically contain these transitions weighted by a Boltzmann factor, the current approach allows one to calculate these transitions individually. Using vibrational frequencies and normal modes computed by the second-order approximate coupled cluster (CC2) method, this formalism is used to compute the single vibronic level (SVL) fluorescence spectra of anthracene. Calculated spectra are in excellent agreement with spectra measured in jet-cooled expansion experiments. Duschinsky mixing is necessary to explain intensities of certain peaks. In a few cases, CC2, however, underestimates Duschinsky mixing, leading to too low peak intensities. An empirical correction of the Duschinsky matrix is presented. The presented method has the potential to facilitate the assignment and interpretation of SVL fluorescence spectra.

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Single vibronic level fluorescence spectra from Ã (1B2u) benzene: Fermi resonances and S0 IVR lifetimes

Cited by 16 publications

References 56 publications

Spectroscopic Properties of Benzene at the Air–Ice Interface: A Combined Experimental–Computational Approach

Spectroscopic Properties of Benzene at the Air–Ice Interface: A Combined Experimental–Computational Approach

Population Diffusion and Equipartition in Quantum Systems of Many Degrees of Freedom

Generating Function Approach to Single Vibronic Level Fluorescence Spectra

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