Some Excited States of the Helium Molecule. I. The Lowest1Sgr;uplus;and3Sgr;gplus;States and the First Excited1Sgr;gplus;States

摘要

We report here some theoretical potential curves for the1Sgr;uplus;(2s,1S0),1Sgr;gplus;(2s,1S0),1Sgr;gplus;(2p0,1S0),3Sgr;gplus;(2s,3S1), and3Sgr;gplus;(2p0,3S1) states of the helium molecule. We find, using a twohyphen;term wavefunction with a mixed basis of Slaterhyphen;type orbitals and elliptic orbitals, that the1Sgr;uplus;potential curve has a maximum of about 0.174 eV atRequals;5.0a0and a minimum atRequals;2.07a0with a rationalized binding energy,EBequals;E(calc.,Re) minus;E(calc.,Requals;infin;) ofEBequals;1.9 eV. We find, in agreement with the recent suggestions of R. S. Mulliken, that the lowest bound state of the helium molecule of symmetry3Sgr;gplus;and the first bound excited state of symmetry1Sgr;gplus;arise from the interactions He(1S0, 1s2)plus;He(3S0, 1s2s),3Sgr;gplus;(2s,3S1), and He(1S0, 1s2)plus;He(1S0, 1s2s),1Sgr;gplus;(2s,1S0), respectively. The1Sgr;gplus;(2s,1S0) and3Sgr;gplus;(2s,3S1) states were also found to have maxima in their computed potential curves. The computed maxima are:1Sgr;gplus;ap;0.7 eV,Requals;4.5a0;3Sgr;gplus;ap;0.8 eV,Requals;3.75a0.