For basic introduction to Rayleigh - Schrödinger Perturbation Theory, see for example lecture notes of Greg Tschumper.

On-line calculation and graphical display
of Rayleigh - Schrödinger perturbation series
for various quantum-mechanical problems

Expanding energy of anharmonic oscillators in powers of a coupling constant g
Name of the problem	Hamiltonian	Click below to calculate the expansion coefficients
Quartic anharmonic oscillator		Run Mathematica program
Sextic anharmonic oscillator		Run Mathematica program
Octic anharmonic oscillator		Run Mathematica program
Cubic anharmonic oscillator		Run Mathematica program
Barbanis potential (two-dimensional anharmonic oscillator)		Run Mathematica program

Expanding energy for a screened Coulomb potential in powers of the screening parameter
Name of the problem	Hamiltonian	Click below to calculate the expansion coefficients
Superposition of the Coulomb and Yukawa potentials		Run Mathematica program

More problems such as relativistic screened Coulomb potentials, Stark, Zeeman effects and 1/D-expansions may be added later.

Other on-line calculations
 Quantum transitions in harmonic oscillators
 Constraint minimization of function of two variables