Excitation energy dependence of the phosphorescence to fluorescence quantum yield ratio of sodium nitrite crystal. An interplay between the energy-dependent intersystem crossing and vibrational relaxation

1982 ◽  
Vol 86 (2) ◽  
pp. 177-181 ◽  
Author(s):  
Fumio Kokai ◽  
Tohru Azumi
Keyword(s):  
Quantum Yield ◽  
Excitation Energy ◽  
Energy Dependence ◽  
Sodium Nitrite ◽  
Vibrational Relaxation ◽  
Fluorescence Quantum Yield ◽  
Yield Ratio ◽  
Intersystem Crossing ◽  
Energy Dependent

Effects of Pressure and Temperature on the Fluorescence Quantum Yield of N-Methylacridone in Solution Interpreted in Terms of the Eyring Transition-StateTheory

1981 ◽  
Vol 36 (5) ◽  
pp. 489-493
Author(s):  
H.-D. Brauer ◽  
R. Schmidt ◽  
B. Hammerich
Keyword(s):  
Quantum Yield ◽  
Fluorescence Quantum Yield ◽  
Energy Gap ◽  
State Theory ◽  
Intersystem Crossing ◽  
Thermally Activated ◽  
Elevated Pressures ◽  
Condon Factors ◽  
Positive Volume ◽  
Franck Condon

Abstract The influence of temperatur and pressure on the fluorescence quantum yield of N-methylacridone (9,10-dihydro-9-oxo-10-methyl-acridine) in toluene in the range of 283-313 K and 1 bar to 2.5 kbar, respectively, has been investigated. Treatment of the data in terms of the Eyring transition-state theory leads to a consistent interpretation of the observed effect. The unusually large increase of the quantum yield with increasing pressure is attributed to a positive volume of activation, ⊿V≠, for the thermally activated S1-T2 intersystem crossing which is known to be the only deactivation process (of the Si-state) competing with fluorescence. Comparison of the values for ⊿H≠, the activation enthalpy of this process, determined at various pressures, indicates a decrease in ⊿H≠ at elevated pressures. Since ⊿H≠ can be associated with the S1-T2 energy gap involved in intersystem crossing, this result further confirms the conclusion that the change in Franck-Condon factors alone cannot account for the decrease in the intersystem crossing rate with increasing pressure.

Parity equilibration in nuclear level densities of 159–166Dy

2020 ◽  
Vol 35 (38) ◽  
pp. 2050315
Author(s):  
R. Razavi ◽  
O. Nouri ◽  
A. Rahmatinejad ◽  
S. Mohammadi
Keyword(s):  
Excitation Energy ◽  
Energy Dependence ◽  
Pair Breaking ◽  
Microscopic Approach ◽  
Nuclear Level ◽  
Pairing Effect ◽  
Level Densities ◽  
Energy Dependent

Excitation-energy dependent parity ratios in the level densities of [Formula: see text] isotopes are calculated within a microscopic approach. Introducing a parity equilibration parameter, energy dependence of the transition from where a single parity dominates to a parity equilibrated state is compared among [Formula: see text] isotopes and its relation to the pairing effect is investigated. A correlation between the pair-breaking and the equilibration of parity distributions is observed for the considered isotopes.

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