Short-time dynamics of 2-thiouracil in the light absorbing S{sub 2}(ππ{sup ∗}) state
Journal Article
·
· Journal of Chemical Physics
- Department of Chemistry, Zhejiang Sci-Tech University, Hangzhou 310018 (China)
- Chemistry College, Beijing Normal University, Beijing 100875 (China)
Ultrahigh quantum yields of intersystem crossing to the lowest triplet state T{sub 1} are observed for 2-thiouracils (2TU), which is in contrast to the natural uracils that predominantly exhibit ultrafast internal conversion to the ground state upon excitation to the singlet excited state. The intersystem crossing mechanism of 2TU has recently been investigated using second-order perturbation methods with a high-level complete-active space self-consistent field. Three competitive nonadiabatic pathways to the lowest triplet state T{sub 1} from the initially populated singlet excited state S{sub 2} were proposed. We investigate the initial decay dynamics of 2TU from the light absorbing excited states using resonance Raman spectroscopy, time-dependent wave-packet theory in the simple model, and complete-active space self-consistent field (CASSCF) and time dependent-Becke’s three-parameter exchange and correlation functional with the Lee-Yang-Parr correlation functional (TD-B3LYP) calculations. The obtained short-time structural dynamics in easy-to-visualize internal coordinates were compared with the CASSCF(16,11) predicted key nonadiabatic decay routes. Our results indicate that the predominant decay pathway initiated at the Franck-Condon region is toward the S{sub 2}/S{sub 1} conical intersection point and S{sub 2}T{sub 3} intersystem crossing point, but not toward the S{sub 2}T{sub 2} intersystem crossing point.
- OSTI ID:
- 22493202
- Journal Information:
- Journal of Chemical Physics, Journal Name: Journal of Chemical Physics Journal Issue: 17 Vol. 143; ISSN JCPSA6; ISSN 0021-9606
- Country of Publication:
- United States
- Language:
- English
Similar Records
Photophysical processes in fluorenone
Photochemical Au(I)–Au(I) Bond Formation: A Battle between Intersystem Crossing and Internal Conversion
Internal conversion and intersystem crossing dynamics based on coupled potential energy surfaces with full geometry-dependent spin–orbit and derivative couplings. Nonadiabatic photodissociation dynamics of NH3(A) leading to the NH(X3Σ–, a1Δ) + H2 channel
Journal Article
·
Thu Oct 19 00:00:00 EDT 1978
· J. Phys. Chem.; (United States)
·
OSTI ID:6781518
Photochemical Au(I)–Au(I) Bond Formation: A Battle between Intersystem Crossing and Internal Conversion
Journal Article
·
Mon Apr 07 20:00:00 EDT 2025
· Journal of Physical Chemistry Letters
·
OSTI ID:3011597
Internal conversion and intersystem crossing dynamics based on coupled potential energy surfaces with full geometry-dependent spin–orbit and derivative couplings. Nonadiabatic photodissociation dynamics of NH3(A) leading to the NH(X3Σ–, a1Δ) + H2 channel
Journal Article
·
Mon Jun 06 20:00:00 EDT 2022
· Physical Chemistry Chemical Physics. PCCP
·
OSTI ID:1978866