Correlations in thermal vibrations of crystal atoms. Effect on dechanneling and bremsstrahlung

Abstract In a crystal, thermal vibrations of neighboring atoms are correlated: long wavelength phonons make them displace in the same direction. These correlations can speed up the dechanneling of axially channeled particles, as shown by a simulation with binary collisions and a Markov chain model of atom vibrations. In the case of e + or e - at small angle with a crystal axis, the correlated vibrations should give rise to a semi-coherent bremsstrahlung on several consecutive atoms of a row.