Interaction energy surfaces for Li(22S) and Li (22P) with H2

Abstract

Interac tion e ne rgy surfaces for the inte rac tion of Li(2'S) a nd Li(2' P) with H, a re ca lcul ated us in g ap proxlll~a t e Hart~ee-Fo c k tn al fun ctIOns. Th e c ross lll g of e nergy c urves is obse rv ed for C' v conformatIon s If th e H, Inte rnucl ea r dIsta nce IS s uffi cle ntl:, la rge. No c ross in g is obse rved for co lin ea r co l-" ss lO ns for a ny H, d ista nce.Th e w av~ functio n of the stron gly a ttrac tiv e sta te involved in th e c rossin g is re la ted to th e me tastabl e negatIv e-Ion sta tes that a re postulated to account for reso na nt elec tron-molec ule scalle rin g. S uc h a c harge-tra nsfe r state ca n on ly be bound for C'v co nformatio ns for th e H, mol ec ul e. The lik e lih ood a nd geome try of th e c ro ss ing co mpl exes for othe r molecul es inte ractin g with alk ali s is di sc ussed in te rm s of the form a tIOn of th ese reso nan ce c harge· tran sfer sta tes.Key Word s: Ene rgy surface; Li(2'S); Li (2' P); H,(X ll;); Hartree-Foc k; e nergy tran sfer; reso na nce state : c harge-tran sfe r.

Quenching of Li ( 2 P) by H 2 : potential energy surfaces, conical intersection seam, and diabatic bases

“…Comparing the energies plotted in Figs. 1 and 2, one concludes that the g 2v portion of the seam of conical intersection is absolutely preeminent in quenching reaction (1).…”

“…The preceding discussion has emphasized the conventional view that for reaction (1) accidental conical intersections of the 1 2 A H and 2 2 A H PESs occur only for g 2v sections where the 1 2 A H Y 2 2 A H states have 2 A 1 Y 2 B 2 symmetries while for general g s geometries only avoided intersections are found. Quite surprisingly we will show that this conventional view of the 1 2 A H À 2 2 A H seam of conical intersection is incomplete.…”

“…Krauss [1] calculated the four lowest potential energy curves of the Li H 2 system in C 2v and C Iv geometries and found crossings only for g 2v or T-shaped geometries (see also Ref. [10]).…”

“…The importance of conical intersections of the two lowest states of Li H 2 in quenching process (1) was ®rst appreciated by Krauss [1] and Tully [4,29]. Krauss [1] calculated the four lowest potential energy curves of the Li H 2 system in C 2v and C Iv geometries and found crossings only for g 2v or T-shaped geometries (see also Ref.…”

Ab initio calculations on the quenching of excited lithium atom by molecular hydrogen. I

“…are a few examples. As to the simplest system Li-H2, Krauss [5] performed the first ab initio calculations of the excited states as well as of the ground state by an open shell HF method. Several years later, Tully [6] constructed the lowest four potential energy surfaces by means of a semiempirical diatomics-in-molecules method and discussed the mechanism of the quenching.…”