The absolute rate of the recombination of three hydrogen atoms is calculated entirely theoretically. The manner in which rotation determines the dimensions of the activated complex in cases having little or no activation energy is discussed. The theoretical data are in good agreement with the experimental rates of Steiner and of Amdur. An immediate consequence of the theory is that energy transfer occurs most effectively among particles which can react with each other, free atoms being more efficient than molecules. A qualitative application of potential surfaces to the problem of energy transfer as met in velocity of sound experiments and in experiments on maintenance of high pressure rates of unimolecular reactions is made.
REFERENCES
1.
Parker Traveling Fellow of Harvard University, 1934–5.
2.
3.
4.
5.
Reference 2(a) Eq. (10). In accordance with the notation used in reference 2(c), κ has been substituted for c, the transmission coefficient, in order to avoid confusion with concentration.
6.
For an excited diatomic oscillator with a reasonable sized dipole the interval before radiation is frequently around In the case of hydrogen, where there is no dipole but only a quadrupole moment, we should expect a mean life of the order of seconds, so that κ may well be as small as
7.
See for example
Kimball
and Eyring
, J. Am. Chem. Soc.
54
, 3381
, etc. (1932
) Figs. 1, 2, and 3 in which this feature is to be observed. In these particular cases, as well as for the three hydrogen atoms, the line makes equal angles with the coordinates and 8.
See Eyring and Polanyi, reference 3. Fig. 16 and accompanying text. Their coordinates and g correspond to our and We should also like to mention that in their Eq. (25) on p. 307 sin φ should be replaced by Accordingly, the angle between b and c in Fig. 17 should be taken as 60°, as we have done in our Fig. 3, where and correspond to b and c, respectively. We are indebted to Dr. O. K. Rice for kindly pointing out this error in sign.
9.
Private communication.
10.
11.
Adams, Smithsonian Mathematical Formulae (1922), p. 105.
12.
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© 1935 American Institute of Physics.
1935
American Institute of Physics
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