Fall-off shape and incubation times in weak-collision thermal unimolecular reactions

1984 ◽  
Vol 62 (1) ◽  
pp. 157-161 ◽  
Author(s):  
H. O. Pritchard
Keyword(s):  
Rate Constant ◽  
Collision Efficiency ◽  
Unimolecular Reactions ◽  
Thermal Reactions ◽  
Efficiency Factors ◽  
New Formula ◽  
Relaxation Structure

A new formula for the weak-collision unimolecular rate constant is readily interpretable in terms of bottleneck concepts. This formula is used to explore the correlation between variations in relaxation structure and fall-off shape in weak-collision thermal unimolecular reactions; some information is also presented relating to collision efficiency factors βc, and to incubation times.It is conjectured that randomisation failure is an important feature which causes near-Lindemann behaviour to occur in practical weak-collision thermal reactions.

Studies in energy transfer II. The isomerization of cyclo propane—a quasi-unimolecular reaction

1953 ◽  
Vol 217 (1131) ◽  
pp. 563-571 ◽  
Keyword(s):  
Energy Transfer ◽  
Rate Constant ◽  
Reaction System ◽  
Thermal Isomerization ◽  
Unimolecular Reaction ◽  
Unimolecular Reactions

The thermal isomerization of cy clopropane to propylene is a homogeneous unimolecular reaction at 490° C and at pressures down of 0·007 cm. The rate constant of the unimolecular reaction falls off by a factor of ten as the pressure in the reaction system is decreased from 8·4 to 0·007 cm. The results are compared with various theories of quasi-unimolecular reactions. The addition of a non-reacting gas to the system counteracts the falling off. The relative efficiencies of a number of gases for maintaining the unimolecular rate constant have been measured.

Über die Verteilung der Lebensdauer in biologischen Kollektiven

1962 ◽  
Vol 17 (6) ◽  
pp. 406-414 ◽  
Author(s):  
A. Sippel ◽  
E. Heim
Keyword(s):  
Gamma Radiation ◽  
Chemical Reactions ◽  
Rate Constant ◽  
Statistical Data ◽  
Survival Curves ◽  
Biological Collections ◽  
New Formula ◽  
Single Constant ◽  
Better Than

In the present publication a relationship is applied to the distributions of life spans of animals, which originally had been found by the authors when studying a quite different problem. The new formula is far simpler and its derivation is more evident than the formulas earlier proposed by GOMPERTZ, MAKEHAM or PERKS 1. Moreover all statistical data taken from literature fit our equation better than any other one.Using the new relationship it is possible to characterize the survival curves of normally ageing biological collections as well as those of collections, the individuals of which are treated with gamma radiation resp. drugs, by one single constant similar to the rate constant in the case of chemical reactions.

Sign in / Sign up

Export Citation Format

Share Document