Excess energy dependence of radiationless transitions in naphthalene vapor: Competition between internal conversion and intersystem crossing

1974 ◽  
Vol 61 (2) ◽  
pp. 582-593 ◽  
Author(s):  
S. F. Fischer ◽  
A. L. Stanford ◽  
E. C. Lim
Keyword(s):  
Energy Dependence ◽  
Internal Conversion ◽  
Excess Energy ◽  
Intersystem Crossing ◽  
Radiationless Transitions

Excess energy dependence of internal conversion in the S1 state of azulene

1988 ◽  
Vol 89 (7) ◽  
pp. 4441-4443 ◽  
Author(s):  
Sudhir K. Kulkarni ◽  
Jonathan E. Kenny
Keyword(s):  
Energy Dependence ◽  
Internal Conversion ◽  
Excess Energy

Theory of nonradiative decay from the lowest singlet state of benzene: Excess energy dependence

1988 ◽  
Vol 53 (9) ◽  
pp. 1902-1909
Author(s):  
Makoto Takahashi ◽  
Tadaaki Ikoma ◽  
Yuichi Fujimura ◽  
Azumao Toyota ◽  
Takeshi Nakajima
Keyword(s):  
Energy Dependence ◽  
Internal Conversion ◽  
Excess Energy ◽  
Electronic Relaxation ◽  
Time Model ◽  
Model Calculations ◽  
Nonradiative Decay ◽  
Drastic Increase ◽  
Nonradiative Decay Rate ◽  
The Difference

A time-independent Green function formalism is developed to study the excess energy dependence on the nonradiative decay in the S1 state of benzene. Effects of purely electronic relaxation (internal conversion, IC) and intramolecular vibrational redistribution, IVR, are taken into account at the same time. Model calculations show that the drastic increase in the nonradiative decay rate at around 3 000 cm-1 excess energy is due to the same onset of both IC and IVR rates. Our theory can explain the difference in rate constant between IVR and IC observed by Moss and Parmenter.

Study of vibronic, spin-orbit and vibronic-spin-orbit couplings of formaldehyde with applications to radiative and non-radiative processes

1976 ◽  
Vol 352 (1668) ◽  
pp. 57-71 ◽  
Keyword(s):  
Rate Constant ◽  
Internal Conversion ◽  
Theoretical Work ◽  
Vibronic Coupling ◽  
Orbit Coupling ◽  
Intersystem Crossing ◽  
Spin Orbit ◽  
Radiative Processes ◽  
Radiationless Transitions ◽  
Radiative Rate

With the recent availability of large amounts of experimental data, theoretical models of radiative and nonradiative processes can be tested in detail. For this purpose, the absolute calculation of radiative and non-­radiative rate constants is required. The expression for the non-radiative rate constant consists of two parts, one from the electronic motion (the pro­moting part) and the other from the nuclear motion (the statistical part). All recent theoretical work has been focused on the calculation of the non-radiative rate constant of one single vibronic state relative to another so that the promoting part of the rate constant is cancelled and hence has been concerned mainly with the Franck–Condon factor calculation (the statistical part of the rate constant). That the calculation of the statistical part of the rate constant cannot provide a critical test for a theory of radiationless transitions is obvious. In the present investigation, the theory of radiationless transitions to be tested is that originally proposed by Robinson and Frosch and later developed by Lin & Bersohn, Siebrand & Henry, Freed, Nitzan & Jortner and Fischer. According to this theory, one way to calculate the promoting part of the non-radiative rate constant is to invoke the vibronic coupling for the internal conversion and to invoke the vibronic coupling plus the spin-orbit coupling and/or the vibronicspin-orbit coupling for the intersystem crossing. A numerical calculation is carried out for the internal conversion 1 A 2 → 1 A 1 and the intersystem crossing 1 A 2 → 3 A 2 of formaldehyde by using simple m. os. For radiative transitions, we calculate the lifetimes of the states, 3 A 2 ( n ↔ π * ), 1 A 2 ( n ↔ π * ), 1 B 1 ( n ↔σ*), and 1 A 1 ( π ↔ π * ). The corresponding transition moments are given. For symmetry forbidden transitions, we compared the Herzberg–Teller theory with the importance of the correc­tion to the breakdown of the adiabatic approximation. It is shown that for formaldehyde, the B.–O. correction is approximately one order of magnitude smaller than the first order vibronic coupling.

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