Theoretical Treatments of Radiationless Transitions

Chin, Chih‐Hao; Shiu, H.Y.-J.; Wang, H.-W.; Chen, Y.-L.; Wang, C.-C.; Lin, S. H.; Hayashi, M.

doi:10.1002/jccs.200600016

Cited by 8 publications

(1 citation statement)

References 109 publications

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“…Another possible radiationless process in the S 1 state is IC, which is caused by vibronic interaction with high-vibrational levels of the S 0 state. The IC rate is given by [4,[25][26][27] A g states are coupled by a b 2u vibration. The IC rate is zero when the equilibrium molecular structure and potential energy curves are identical for the S 0 and S 1 states.…”

Section: Resultsmentioning

confidence: 99%

Ultrahigh-resolution laser spectroscopy of the S1 1B2← S0 1A transition of perylene

Kowaka¹,

Suganuma²,

Ashizawa³

et al. 2010

Journal of Molecular Spectroscopy

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a b s t r a c tA rotationally resolved ultrahigh-resolution fluorescence excitation spectrum of the S 1 S 0 transition of perylene has been observed using a collimated supersonic jet technique in conjunction with a single-mode UV laser. We assigned 1568 rotational lines of the 0 0 0 band, and accurately determined the rotational constants. The obtained value of inertial defect was positive, accordingly, the perylene molecule is considered to be planar with D 2h symmetry. We determined the geometrical structure in the S 0 state by ab initio theoretical calculation at the RHF/6-311+G(d,p) level, which yielded rotational constant values approximately identical to those obtained experimentally. Zeeman broadening of each rotational line with the external magnetic field was negligibly small, and the mixing with the triplet state was shown to be very small. This evidence indicates that intersystem crossing (ISC) in the S 1 1 B 2u state is very slow. The rate of internal conversion (IC) is also inferred to be small because the fluorescence quantum yield is high. The rotational constants of the S 1 1 B 2u state were very similar to those of the S 0 1 A g state. The slow internal conversion (IC) at the S 1 zero-vibrational level is attributed to a small structural change upon electronic transition.

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Section: Resultsmentioning

confidence: 99%

Ultrahigh-resolution laser spectroscopy of the S1 1B2← S0 1A transition of perylene

Kowaka¹,

Suganuma²,

Ashizawa³

et al. 2010

Journal of Molecular Spectroscopy

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Theoretical study of the absorption and emission spectrum and non‐adiabatic excited state dynamics of gas‐phase xanthone

Chin

Zhu

Zhang

2023

J Chinese Chemical Soc

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The ground, singlet, and triplet excited state structures (S1, S2, T1, and T2) of xanthone have been calculated and characterized in the adiabatic representation by using time‐dependent density functional theory (TDDFT). However, the fast intramolecular transition mechanisms of xanthone are still under debate, and so we perform non‐adiabatic excited state dynamics of the photochemistry of xanthone gas phase and find that it follows El‐Sayed's rule. Electronic transition mechanism of xanthone is sequential from the S2 state: the singlet internal conversion (IC) time from S2 (1ππ*) to S1 (1nπ*) is 3.85 ps, the intersystem crossing (ISC) from S1 (1nπ*) to T2 (3ππ*) takes 4.76 ps, and the triplet internal conversion from T2 (3ππ*) to T1 (3nπ*) takes 472 fs. The displaced oscillator, Franck–Condon approximation, and one‐photon excitation equations were used to simulate the absorption spectra of S0 → S2 transition, with v55 being most crucial for S0 structure; the fluorescence spectra of S1 → S0 transition with v47 for S1; and the phosphorescence spectra of T1 → S0 transition with v4 for T1. Our method can reproduce the experimental absorption, fluorescence, and phosphorescence spectra of gas‐phase xanthone.

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Quantum Chemistry Study on Internal Conversion of Diphenyldibenzofulvene in Solid Phase

Hayashi

Lin

2011

J. Phys. Chem. A

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We investigate the nonradiative decay process of diphenyldibenzofulvene (DPDBF) in solid phase by using the quantum chemistry methods. To carry out the nonradiative rate constant calculation, we construct a solid phase model based on the ONIOM method. The geometry of the DPDBF molecule is optimized for the ground state by DFT and the first excited state by TD-DFT, and the corresponding vibrational frequencies and normal coordinates are computed. Under displaced-distorted harmonic oscillator potential approximation, Huang-Rhys factors are obtained. Vibronic coupling constants are calculated as a function of the normal mode based on Domcke's scheme. We find that vibronic coupling constants of 12 modes with large reorganization energies are of similar order, and if this result is still valid for other modes, the internal conversion rate would be determined by high frequency modes because they have a significant nuclear factor that is related to Franck-Condon overlap intergrals. We also find that geometrical changes are suppressed due to the stacking effect, which yields small Huang-Rhys values in the solid phase.

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Theoretical Treatments of Radiationless Transitions

Cited by 8 publications

References 109 publications

Ultrahigh-resolution laser spectroscopy of the S1 1B2← S0 1A transition of perylene

Ultrahigh-resolution laser spectroscopy of the S1 1B2← S0 1A transition of perylene

Theoretical study of the absorption and emission spectrum and non‐adiabatic excited state dynamics of gas‐phase xanthone

Quantum Chemistry Study on Internal Conversion of Diphenyldibenzofulvene in Solid Phase

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