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Adiabatic perturbation of a periodic potential. II. (Russian. English summary) Zbl 0643.34068
[For part I see ibid. 58, No.2, 233-243 (1984; Zbl 0534.34064).]
For the equation $$-\psi ''+p(x)\psi +q(\epsilon x)\psi =0$$, p-periodic function, $$\epsilon\to 0$$, behaviour of solutions in neighbourhood of two close turning points is studied. The results give mathematically consistent description of the electric breakdown effect in the Bloch electron theory.

##### MSC:
 3.4e+21 Singular perturbations, turning point theory, WKB methods for ordinary differential equations