INTRINSIC ORDERING OF QUASI-ENERGY STATES FOR MIXED REGULAR CHAOTIC QUANTUM-SYSTEMS - ZEROS OF THE HUSIMI DISTRIBUTION/

A method is proposed which allows an intrinsic ordering of the quasien ergy states for a time-periodic quantum system according to the number of essential zeros of the Husimi distribution in phase space. The cor responding classical system shows a typical mixed dynamics with coexis ting regular and chaotic regions in phase space. The-ordering of state s allows a straight forward comparison with semiclassical quantities. Moreover, a direct connection of the organization of zeros with the un derlying classical phase space dynamics is demonstrated.