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.

scholarly journals Fluorescence Property and its Magnetic Field Dependence Across the Photodissociation Threshold of CH3CHO and CD3CDO in a Supersonic Jet

1994 ◽  
Vol 13 (3-4) ◽  
pp. 207-222 ◽  
Author(s):  
Nobuhiro Ohta
Keyword(s):  
Magnetic Field ◽  
Excitation Energy ◽  
Triplet State ◽  
Energy Dependence ◽  
Level Density ◽  
Excess Energy ◽  
Zero Field ◽  
Statistical Limit ◽  
Fluorescence Characteristics ◽  
Dissociation Threshold

Fluorescence characteristics of jet-cooled acetaldehyde at zero field is confirmed to change from the small molecule behavior to the statistical limit behavior in CH3CHO and to the intermediate case in CD3CDO, as the excitation energy increases across the dissociation threshold located below 320 nm. The excitation energy dependence both of the intensity and of the lifetime of the slow fluorescence shows that the dissociation rate becomes faster abruptly with increasing excess energy above the threshold, and the excess energy dependence above the threshold seems to be more drastic in CH3CHO than in CD3CDO. External magnetic field as well as the dissociation in the triplet state plays a role to increase the level density of the triplet state coupled to S1. On excitation below the dissociation threshold, the magnetic quenching of fluorescence becomes more efficient with increasing excess energy and the efficiency of the quenching is larger in CD3CDO than that in CH3CHO by a factor of about 2. On excitation above the threshold, however, the efficiency becomes lower with increasing excitation energy. Thus, the magnetic field effects on fluorescence also change drastically across the dissociation threshold.

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