Fm. Fernandez et R. Guardiola, ACCURATE EIGENVALUES AND EIGENFUNCTIONS FOR QUANTUM-MECHANICAL ANHARMONIC-OSCILLATORS, Journal of physics. A, mathematical and general, 26(23), 1993, pp. 7169-7180
The representation of the Taylor expansion of the logarithmic-derivati
ve of the wavefunction by means of a Pade approximant, followed by an
appropriate quantization condition, proves a powerful way of obtaining
accurate eigenvalues of the Schrodinger equation. In this paper we in
vestigate in detail some of the interesting features of this approach,
termed Riccati-Pade method (RPM), by means of its application to anha
rmonic oscillators. We analyse the occurrence of many roots in the nei
ghborhoods of the physical eigenvalues in the weak-coupling regime, an
d also obtain accurate coefficients of the strong-coupling expansion.
We finally investigate the global and the local accuracy of the Rpm ei
genfunctions.