Morse Potential Oscillator

Anharmonic oscillator: bound states below D, dissociation above. Phase portrait shows transition.

E = 0.50 D | bound oscillation

Energy E/D: 0.50 α (width): 1.0 D (depth): 1.0

V(r) = D(1−e^{−α(r−r₀)})². At E < D: bounded anharmonic oscillation (closed phase curve). At E = D: particle barely escapes (separatrix). At E > D: dissociation — open phase curve. Unlike harmonic oscillator, frequency depends on energy (anharmonicity). Real diatomic molecules use Morse potential.