scholarly journals Internal Conversion versus Intersystem Crossing: What Drives the Gas Phase Dynamics of Cyclic α,β-Enones?

2014 ◽  
Vol 118 (12) ◽  
pp. 2279-2287 ◽  
Author(s):  
Oliver Schalk ◽  
Michael S. Schuurman ◽  
Guorong Wu ◽  
Peter Lang ◽  
Melanie Mucke ◽  
...  
Keyword(s):  
Gas Phase ◽  
Internal Conversion ◽  
Intersystem Crossing ◽  
Phase Dynamics

Internal conversion and intersystem crossing dynamics of uracil upon double thionation: a time-resolved photoelectron spectroscopy study in the gas phase

2020 ◽  
Vol 22 (27) ◽  
pp. 15608-15615
Author(s):  
Abed Mohamadzade ◽  
Susanne Ullrich
Keyword(s):  
Gas Phase ◽  
Photoelectron Spectroscopy ◽  
Internal Conversion ◽  
Intersystem Crossing ◽  
Spectroscopy Study ◽  
Time Resolved

Gas-phase photophysics of 2,4-dithiouracil studied by time-resolved photoelectron spectroscopy.

scholarly journals Ultrafast intersystem crossing in xanthone from wavepacket dynamics

2021 ◽  
Author(s):  
Marc Alías Rodríguez ◽  
Coen De Graaf ◽  
Miquel Huix-Rotllant
Keyword(s):  
Excited State ◽  
Gas Phase ◽  
Internal Conversion ◽  
Singlet State ◽  
Minimum Energy ◽  
Intersystem Crossing ◽  
Singlet Excited State ◽  
Polar Solvents ◽  
Aromatic Ketones ◽  
Wavepacket Dynamics

Most aromatic ketones containing first-row elements undergo unexpectedly fast intersystem crossing in few tens of picoseconds and a quantum yield close to unity. Among them, xanthone (9H-xanthen-9-one) possesses one of the fastest singlet-triplet rates of ~1.5 ps. The exact mechanism of this unusually fast transition is still under debate. Here, we perform the wavepacket dynamics of the photochemistry of xanthone in the gas phase and in polar solvents. We show that xanthone follows El-Sayed's rule for intersystem crossing. From the second singlet excited state, the mechanism is sequential: (i) an internal conversion between singlets 1pipi*-1npi* (85 fs), (ii) an intersystem crossing 1npi*-3pipi* (2.0 ps), and (iii) an internal conversion between triplets 3pipi*-3npi* (602 fs). Each transfer finds its origin in a barrierless access to electronic state intersections. These intersections are close to minimum energy structures, allowing for efficient transitions from the initial singlet state to the triplets.

scholarly journals Ultrafast intersystem crossing in xanthone from wavepacket dynamics simulations

2021 ◽  
Author(s):  
Marc Alías Rodríguez ◽  
Coen De Graaf ◽  
Miquel Huix-Rotllant
Keyword(s):  
Gas Phase ◽  
Internal Conversion ◽  
Minimum Energy ◽  
Dynamics Simulation ◽  
Intersystem Crossing ◽  
Singlet Excited State ◽  
Radiationless Transition ◽  
Wavepacket Dynamics ◽  
Dynamics Simulations ◽  
Triplet Transition

Most aromatic ketones containing first-row elements undergo unexpectedly fast intersystem crossing in few tens of picosecond and a quantum yield close to unity. Among them, xanthone (9H-xanthen-9-one) possesses one of the fastest intersystem crossing rates of ~1.5 ps, despite containing only first-row elements. The exact mechanism of this unusually fast singlet-triplet transition is still under debate. Here, we perform a complete wavepacket dynamics simulation of the internal conversion and intersystem crossing reactions of xanthone in the gas phase. We show that xanthone follows El-Sayed's rule for intersystem crossing. From the second singlet excited state, the mechanism is sequential: (i) an internal conversion between singlets 1pipi*-1npi* (~0.14 fs), (ii) an intersystem crossing 1npi*-3pipi* (~1.8 ps), and (iii) an internal conversion between triplets 3pipi*-3npi* (~27 ps). Each transfer finds its origin in a barrierless access to electronic state intersections. These intersections are close to minimum energy structures, allowing for an efficient radiationless transition from 1pipi* to 3npi*.

Luminescence Quenching of Rhodamines by Cyclooctatetraene

1987 ◽  
Vol 42 (9) ◽  
pp. 1009-1013 ◽  
Author(s):  
P. Targowski ◽  
B. Ziętek ◽  
A. Bączyński
Keyword(s):  
Rhodamine B ◽  
Rate Constants ◽  
Internal Conversion ◽  
Rhodamine 6G ◽  
Second Order ◽  
Luminescence Quenching ◽  
Intersystem Crossing ◽  
Order Rate ◽  
Quenching Process

Cyclooctatetraene (COT) as a quencher of fluorescence of a series of Rhodamine solutions was studied. The second order rate constants for the quenching process of Rhodamine 110, Rhodamine 19 pchl., Rhodamine 6G pchl., Rhodamine 6G, Tetramethylrhodamine, Rhodamine B and Rhodamine 3B pchl. are given. It was found that COT enhances rather intersystem crossing than internal conversion.

scholarly journals 2-Thiouracil intersystem crossing photodynamics studied by wavelength-dependent photoelectron and transient absorption spectroscopies

2017 ◽  
Vol 19 (30) ◽  
pp. 19756-19766 ◽  
Author(s):  
José A. Sánchez-Rodríguez ◽  
Abed Mohamadzade ◽  
Sebastian Mai ◽  
Brennan Ashwood ◽  
Marvin Pollum ◽  
...  
Keyword(s):  
Gas Phase ◽  
Transient Absorption ◽  
Wavelength Dependence ◽  
Excitation Wavelength ◽  
Intersystem Crossing ◽  
Excitation Wavelength Dependence

The excitation-wavelength dependence of the intersystem crossing (ISC) dynamics of 2-thiouracil was studied in gas-phase and solution.

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