ODD AND EVEN INTRINSIC MODES IN DIATOMIC NONLINEAR LATTICES

Systematic simulations of a one-dimensional diatomic dynamical lattice with cubic and quartic anharmonicity demonstrate that the odd (Siever s-Takeno) intrinsic mode is stable at relatively low frequencies, bein g changed by the even (Page) one at some critical frequency. The trans ition between the two modes is hysteretic, i.e., it depends upon the d irection of change of the frequency. The critical frequency is a growi ng function of the mass difference between the particles with the odd and even numbers, but it proves to be practically independent of the r atio between the quadratic and cubic terms in the equations of motion. Copyright (C) 1998 Elsevier Science B.V.