ASYMMETRICAL QUANTUM SEXTIC ANHARMONIC-OSCILLATOR - EIGENSTATES AND THERMAL-PROPERTIES

The state-dependent-diagonalization (SDD) method is applied to the eig envalue problem of an asymmetrical quantum sextic anharmonic oscillato r with the potential energy V(x) = 1/2x(2) + Sigma(j=3)(6)A(j)x(j), wh ere A(6)>0. This method treats the eigenstates individually and is esp ecially efficient for the high excited states. Three representative po tentials have been examined: (a) A(j) = 1, (b) A(j) = 10, and (c) the A(j)'s are chosen to fit the vibrational potential energy of the hydro gen molecule. By the SDD method, the eigenfunction and eigenvalue of e ach of the first 100 eigenstates of the above potentials can be accura tely determined by diagonalizing matrices of sizes less than 95 x 95. Results for the thermal variations of the heat capacity and the first six cumulants of the vibrational displacement are also presented. [S10 50-2947(98)08210-9].