Théorie des chaines de collisions focalisantes: Part 1-4

Part 1
The hard sphere model describes the focusing processes in a qualitative manner. A more complete theory should take into account: the decrease in the energy transmitted from one atom to the next, the real interatomic potential, the influence of neighbouring atomic rows, and the distortion of these rows. The effect of these various factors will be discussed in this and following papers. The present paper commences with a general introduction to the theory of focusing processes. The energy decrease along a collision chain is then considered for the case of an alloy.

Part 2
A consistent theory of focusing processes should take the following effects into account: the decrease of the energy transmitted from one atom to the next, the real interatomic potential, the distortion of the atomic rows, and the influence of neighbouring atomic rows. The decrease of the energy along a collision chain has been considered in a previous paper [10] in which the case of an alloy was discussed. The present paper contains firstly a discussion of the effects of an interatomic potential which is different from the hard-sphere potential. Collision chains along non-linear atomic row’s are then investigated. The case of (1123) rows in h.c.p. metals is considered throughout the paper.


Part 3
The decrease of energy along a collision chain has been considered in a previous paper [10], the case of an alloy being discussed. Inasecond paper [19], the effects associated with the deviation of the interatomic potential are discussed and an investigation made of collision chains propagating along non-linear atomic rows. The case of <1123> rows in h.c.p. metals is discussed in this latter paper. In the present paper, a study is made of “assisted focusing processes" i.e. of the influence of neighbouring atomic rows. Rumerical data for copper is given (focusing parameters, and focusing energy and range), which is compared with the results of Vineyard et al. [13] obtained by numerical calculations.

Part 4
The theory of focusing chains has been developed in three preceding papers, and in the present paper their influence on "thermalization” is investigated. BRINKMANN's model is generalized by taking into account the influence of focusing processes on the initial distribution of thermal spikes. The "dense region”, which contains all the interstitial atoms, appears to be surrounded by an "excited region”. the mean thickness of which depends on the range of the focusing chains. The time dependence of a thermal spike is then studied. The conventional treatment of this problem .starts with the classical macroscopic heat-flow theory; hut the present study indicates the need for a proper microscopic derivation.