OBSERVATION OF BOUND-FREE-BOUND TRIPLET ABSORPTION-BANDS IN LI2

Multiphoton ionization spectroscopy has yielded the first evidence for triplet absorption bands in Li2 in the spectral region from 6215 to 5875 . This spectrum is the first of a new class of spectra resulting from a two-photon transition from a bound (u3+) van der Waals state to a previously unknown bound Λu3 state (where Λ=0,1,or2) through an intermediate free state (Πg3). The final state either autoionizes or collisionally forms the g2+ ground state of Li2+. © 1979 The American Physical Society.