Theoretical study of H2+ spectroscopic properties. II. The 2pπ/subu/ electronic state

Vibration-rotation eigenenergies are computed for the (2pπu) 2Πu state of H2+. Spectroscopic constants Yij are found from Dunham power series expansions of the vibrational potential and also from the eigenenergies. The Yij are much smaller in magnitude than H2+ ground state values because of the 2p πu broadened potential and larger equilibrium separation re. The eigenenergies are used to determine Bν, Dν, and Hν for all bound vibrational states, i.e., for 0 ≤ ν ≤ 11. Both the ΔG and Bν curves have negative curvature at all ν. The Dν and Hν curves are similar in shape to the respective curves for the H2+ ground state. The Dν's decrease slowly at low ν but increase rapidly near dissociation. The Hν curve has a small negative initial slope; the Hν's decrease very rapidly, becoming negative, at high ν. Origin wavelengths are listed for a few H2+ 2p πu−1sσg bands predicted to be intense on the basis of the classical Franck-Condon principle; these lie in the Lyman α region.