Quenching of excited states of fluorobenzene in the gas phase

1971 ◽  
Vol 75 (24) ◽  
pp. 3662-3667 ◽  
Author(s):  
Kh. Al-Ani ◽  
David Phillips
Keyword(s):  
Gas Phase ◽  
Excited States

EXCITED STATES OF ACETYLENE AND THEIR ROLE IN PYROLYSIS

1958 ◽  
Vol 36 (1) ◽  
pp. 131-136 ◽  
Author(s):  
G. J. Minkoff
Keyword(s):  
Liquid Phase ◽  
Induction Period ◽  
Gas Phase ◽  
Recent Work ◽  
Excited States ◽  
Trans Configuration ◽  
Detailed Mechanism ◽  
Vinyl Polymerization ◽  
Gas Phase Polymerization ◽  
Kinetic Form

Previous theories of acetylene pyrolysis are reviewed in the light of recent work by Minkoff, Newitt, and Rutledge. It is shown that the relatively large rates observed at the beginning of the induction period do not agree with mechanisms involving the intervention of comparatively stable dimers. The required kinetic form is obtained, however, if a triplet diradical is produced on the surface in a bimolecular process, followed by gas phase polymerization, with some chain ending on the surface. The detailed mechanism closely resembles Flory's scheme for liquid phase vinyl polymerization. The shape of the radical is discussed, and it is suggested that the trans-configuration leads to polymerization, while the cis facilitates dehydrogenation.

Excited-Atom Production by Electron Bombardment of Alkali-Halides

1986 ◽  
Vol 75 ◽  
Author(s):  
R. E. Walkup ◽  
Ph. Avouris ◽  
A. P. Ghosh
Keyword(s):  
Gas Phase ◽  
Excited States ◽  
Ground State ◽  
Excited Atom ◽  
Alkali Halides ◽  
Electron Bombardment ◽  
Secondary Electrons ◽  
Excited Atoms ◽  
Positive Ions ◽  
Electronically Excited

AbstractWe present experimental results which suggest a new mechanism for the production of excited atoms and ions by electron bombardment of alkali-halides. Doppler shift measurements show that the electronically excited atoms have a thermal velocity distribution in equilibrium with the surface temperature. Measurements of the absolute yield of excited atoms, the distribution of population among the excited states, and the dependence of yield on incident electron current support a model in which excited atoms are produced by gas-phase collisions between desorbed ground-state atoms and secondary electrons. Similarly, gas-phase ionization of ground-state neutrals by secondary electrons accounts for a substantial portion of the positive ions produced by electron bombardment of alkali-halides.

scholarly journals Communication: Evidence for dipole-bound excited states in gas-phase I− ⋅ MI (M = Na, K, Cs) anionic salt microclusters

2015 ◽  
Vol 143 (10) ◽  
pp. 101103 ◽  
Author(s):  
Andrew J. A. Harvey ◽  
Naruo Yoshikawa ◽  
Jin-Guo Wang ◽  
Caroline E. H. Dessent
Keyword(s):  
Phase I ◽  
Gas Phase ◽  
Excited States ◽  
Anionic Salt

scholarly journals Photochemistry of Thymine in Protic Polar Nanomeric Droplets Using Electrostatic Embeding TD-DFT/MM

Molecules ◽  
2021 ◽  
Vol 26 (19) ◽  
pp. 6021
Author(s):  
Miquel Huix-Rotllant
Keyword(s):  
Gas Phase ◽  
Excited States ◽  
Ground State ◽  
Potential Energy Surfaces ◽  
Radiative Decay ◽  
Td Dft ◽  
Dna Photodamage ◽  
Solvent Molecules ◽  
Energy Surfaces ◽  
Electrostatic Embedding

Thymine photochemistry is important for understanding DNA photodamage. In the gas phase, thymine undergoes a fast non-radiative decay from S2 to S1. In the S1 state, it gets trapped for several picoseconds until returning to the ground-state S0. Here, we explore the electrostatic effects of nanomeric droplets of methanol and water on the excited states of thymine. For this purpose, we develop and implement an electrostatic embedding TD-DFT/MM method based on a QM/MM coupling defined through electrostatic potential fitting charges. We show that both in methanol and water, the mechanism is similar to the gas phase. The solvent molecules participate in defining the branching plane of S0/S1 intersection and have a negligible effect on the S1/S2 intersection. Despite the wrong topology of the ground/excited state intersections, electrostatic embedding TD-DFT/MM allows for a fast exploration of the potential energy surfaces and a qualitative picture of the photophysics of thymine in solvent droplets.

GAS-PHASE ELECTRONIC SPECTRA OF POLYACETYLENE CATIONS: RELEVANCE OF HIGHER EXCITED STATES

2010 ◽  
Vol 140 (1) ◽  
pp. 203-205 ◽  
Author(s):  
C. A. Rice ◽  
V. Rudnev ◽  
R. Dietsche ◽  
J. P. Maier
Keyword(s):  
Gas Phase ◽  
Excited States ◽  
Electronic Spectra ◽  
Higher Excited States
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