# Rayleigh - Schrödinger perturbation series for two-dimensional anharmonic oscillatorwx2x2/2 + wy2y2/2 + g1/2xy2

Enter oscillator quantum numbers Enter frequencies of vibrations nx = ny = 0, 1, 2, 3, ... wx = wy = Integer, rational or floating-point numbers N = 1, 2, 3, ... ndigits = 16 for standard, 17, 18, 19, ... for multiple precision, or 0 for exact symbolic calculations Default response

 H = H0 + g1/2 x y2 Hamiltonian of the problem E(g) = E0 + E1 g + ... + EN gN Perturbation expansion of energy H0 = px2/2 + py2/2 + wx2 x2/2 + wy2 y2/2 Hamiltonian of harmonic oscillator E0 = (nx + 1/2)wx + (ny + 1/2)wy Unperturbed harmonic-oscillator energy wx, wy Frequencies of normal-mode vibrations g Small perturbation parameter nx, ny Harmonic oscillator quantum numbers N Order of perturbation theory  110 coefficients for wx=1, wy=1.1, and nx=0, nx=0, nx=0, nx=1, nx=0, nx=2, nx=0, nx=4, nx=1, nx=0, nx=1, nx=2, nx=2, nx=0, nx=2, nx=1, nx=2, nx=2, nx=3, nx=0, nx=3, nx=1, nx=4, nx=0, nx=5, nx=0, calculated earlier  On-line calculation of Rayleigh - Schrödinger perturbation series

Designed by A. Sergeev