ENERGY TRANSFER IN THE RADIOLYSIS OF CYCLOPENTANE–CYCLOHEXANE MIXTURES

1964 ◽  
Vol 42 (12) ◽  
pp. 2872-2879 ◽  
Author(s):  
J. A. Stone
Keyword(s):  
Energy Transfer ◽  
Carbon Tetrachloride ◽  
Radical Change ◽  
Energy Migration ◽  
Hydrogen Atoms ◽  
Show Evidence

Energy transfer in the radiolysis of cyclopentane–cyclohexane mixtures has been studied by observing the yields of HD and D2 obtained when small amounts of cyclohexane-d12 are added. Energy migration occurs from cyclopentane to cyclohexane but this transfer can be prevented by the addition of carbon tetrachloride or iodine. The relative yields of the dimers (C6H11)2, C6H9C6H11, and (C5H3)2 show that the •C6H11 and •C5H9 radicals, which are the precursors of the dimers, can abstract hydrogen atoms from the solvent and may thus change their identity. Added iodine or carbon tetrachloride removes the diffusing radicals, and the residual dimer yield, which is unaffected by solute, has a composition determined solely by the composition of the mixtures. The yields of cyclohexene and cyclopentene show evidence of both energy transfer and radical change of identity.

RADIATION CHEMISTRY OF CYCLOHEXANE: VI. DILUTE SOLUTIONS OF CARBON TETRACHLORIDE AND CHLOROFORM IN CYCLOHEXANE

1964 ◽  
Vol 42 (3) ◽  
pp. 669-681 ◽  
Author(s):  
J. A. Stone ◽  
P. J. Dyne
Keyword(s):  
Carbon Tetrachloride ◽  
Chemical Reaction ◽  
Physical Process ◽  
Radical Scavenging ◽  
Radiation Chemistry ◽  
Hydrogen Yield ◽  
Halogenated Compounds ◽  
Dilute Solutions ◽  
Hydrogen Atoms

A study of the effect of the addition of small amounts (<3.5%) of the halogenated compounds CCl4, CHCl3, and CDCl3 on the radiolysis of cyclohexane has shown that processes other than radical scavenging occur. At the lowest concentrations of solute that it was practical to employ (0.004 M) cyclohexyl radicals were scavenged without a corresponding reduction in the hydrogen yield. At higher solute concentrations G(H2) was reduced by a physical process which did not involve the scavenging of thermal hydrogen atoms but did lead to chemical reaction involving the solute.

Topological molecular nanocarbons: All-benzene catenane and trefoil knot

Science ◽  
2019 ◽  
Vol 365 (6450) ◽  
pp. 272-276 ◽  
Author(s):  
Yasutomo Segawa ◽  
Motonobu Kuwayama ◽  
Yuh Hijikata ◽  
Masako Fushimi ◽  
Taishi Nishihara ◽  
...  
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Energy Transfer ◽  
Magnetic Resonance ◽  
Dynamic Behavior ◽  
Enantiomer Separation ◽  
Hydrogen Atoms ◽  
Interlocked Molecules ◽  
Benzene Rings ◽  
Trefoil Knot ◽  
Synthetic Routes

The generation of topologically complex nanocarbons can spur developments in science and technology. However, conventional synthetic routes to interlocked molecules require heteroatoms. We report the synthesis of catenanes and a molecular trefoil knot consisting solely of para-connected benzene rings. Characteristic fluorescence of a heterocatenane associated with fast energy transfer between two rings was observed, and the topological chirality of the all-benzene knot was confirmed by enantiomer separation and circular dichroism spectroscopy. The seemingly rigid all-benzene knot has rapid vortex-like motion in solution even at –95°C, resulting in averaged nuclear magnetic resonance signals for all hydrogen atoms. This interesting dynamic behavior of the knot was theoretically predicted and could stimulate deeper understanding and applications of these previously untapped classes of topological molecular nanocarbons.

Depolarization of Photoluminescence of Isotropic Solutions Produced by Excitation Energy Migration

1987 ◽  
Vol 42 (8) ◽  
pp. 813-818
Author(s):  
A. Kawski ◽  
J. Kamiński
Keyword(s):  
Experimental Data ◽  
Energy Transfer ◽  
Excitation Energy ◽  
Master Equation ◽  
Shell Model ◽  
Excitation Energy Transfer ◽  
Critical Distance ◽  
Energy Migration ◽  
Isotropic Solution ◽  
Fluorescence And Phosphorescence

A theory of the excitation energy transfer between like molecules in isotropic solution based on a centre or shell model of a primarily excited luminescent molecule and on the extended Förster “excitation master equation” has been elaborated. Fluorescence and phosphorescence depolarization are shown to be governed by singlet-singlet energy migration and described by the same expression. The comparison of the theoretical curve with the experimental data obtained by Gondo et al. (1975) for benzo[f]quinoline in ethanol glass at 77 K results in the following critical distance R0 for the excitation energy migration: 21.5 Å for fluorescence and phosphorescence, respectively.

Study on Energy Transfer and Energy Migration of Ca2Gd8(SiO4)6O2:Dy3+ Phosphor Films

2011 ◽  
Vol 11 (11) ◽  
pp. 9714-9716 ◽  
Author(s):  
X. Q. Wang ◽  
X. M. Han ◽  
C. M. Zhen
Keyword(s):  
Energy Transfer ◽  
Energy Migration

Vibrational relaxation in gases

1959 ◽  
Vol 253 (1273) ◽  
pp. 277-288 ◽  
Keyword(s):  
Energy Transfer ◽  
Relaxation Process ◽  
Vibrational Relaxation ◽  
Vibrational Energy ◽  
Ultrasonic Waves ◽  
The Other ◽  
Ultrasonic Frequency ◽  
Hydrogen Atoms ◽  
Torsional Mode ◽  
Fundamental Frequencies

The velocity of ultrasonic waves has been measured in a number of gases at 25°C and for values of the ratio, ultrasonic frequency/pressure, ranging from 2 x 10 5 to 2 x 10 7 c s -1 atm -1 . Dispersion, corresponding to a single vibrational relaxation process was shown by acetylene, CD 3 Br and hexafluoro-ethane; and, to a double relaxation process, by ethane. Incipient dispersion was shown by propane, ethyl chloride, ethyl fluoride and dimethyl ether. No dispersion was shown by 1.1-difluoro-ethane, n -butane, iso -butane, neo -pentane and ammonia. Correlation of these with previous results leads to the conclusion that: ( а ) For molecules with a distribution of fundamental frequencies, such that there is only a small gap between the lowest and the remaining frequencies, vibrational activation enters via the lowest mode and spreads rapidly to the other modes, giving rise to a single relaxation process involving the whole of the vibrational energy. The chief factors determining the probability of excitation of the lowest mode are its frequency and the presence or absence of hydrogen atoms in the molecule. Molecules containing two or more hydrogen atoms suffer translational-vibrational energy transfer very much more easily than other molecules. Deuterium has almost the same effect as hydrogen. ( b ) For molecules, in which there is a large gap between the lowest and the remaining fundamental frequencies, a double relaxation process occurs. The complex energy transfer probabilities involved do not fit the same quantitative functional relation with vibrational frequency as in ( a ) above. ( c ) Torsional oscillations due to hindered internal rotation behave similarly to other fundamental modes. For molecules in which there is a large gap between the torsional frequency and the other modes (e. g. ethane) a double relaxation process occurs as in ( b ). Where there is no such gap, vibrational energy enters all modes via the torsional mode as in ( a ).

The Reaction of Hydrogen Atoms with Carbon Tetrachloride

1938 ◽  
Vol 6 (12) ◽  
pp. 811-818 ◽  
Author(s):  
John E. Vance ◽  
W. C. Bauman
Keyword(s):  
Carbon Tetrachloride ◽  
Hydrogen Atoms

scholarly journals Luminescence: Probing Energy Migration through Precise Control of Interfacial Energy Transfer in Nanostructure (Adv. Mater. 6/2019)

2019 ◽  
Vol 31 (6) ◽  
pp. 1970041 ◽  
Author(s):  
Bo Zhou ◽  
Jinshu Huang ◽  
Long Yan ◽  
Xuelong Liu ◽  
Nan Song ◽  
...  
Keyword(s):  
Energy Transfer ◽  
Interfacial Energy ◽  
Energy Migration ◽  
Precise Control

Competition between Energy Transfer and Energy Migration Processes in Neat and Eu3+-Doped TbPO4

2018 ◽  
Vol 122 (12) ◽  
pp. 6858-6864 ◽  
Author(s):  
Irene Carrasco ◽  
Fabio Piccinelli ◽  
Ivo Romet ◽  
Vitali Nagirnyi ◽  
Marco Bettinelli
Keyword(s):  
Energy Transfer ◽  
Energy Migration
Sign in / Sign up

Export Citation Format

Share Document