Even parity, odd n solutions

The odd parity states have the same boundary conditions as tt(r), namely u 0) = 0 and u r oo) 0. They are formed by matching u r) with —u —r) at the origin. Thus, for even n the binding energies are 

The particle-hole continuum is trivially found by setting V r = 0) in eqn (D.17). The onset of the particle-hole continumn is at t/ + 2A — 2Ei K)/a K), so the exciton energies relative to the groimd state are 

The average particle-hole separation, ro, may be found from the expectation value of r, 

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