Calculation of rotational–vibrational preionization in H2 by multichannel quantum defect theory

Multichannel quantum defect theory is adapted to treat simultaneous rotational and vibrational preionization in H2. The strongly preionized spectrum between the N+=0 and N+=2 rotational thresholds of photoionization of H2X1Σg+(J″=0, v″=0) to produce H2+X2Σg+(N+, v+=0) is computed as example and good agreement is obtained with the photoionization data of Dehmer and Chupka.