The spectral line of a dopant molecule B in a cluster B·An of solvent molecules A has usually been thought to converge to the bulk (gas-to-condensate) shift as n → ∞. Size-resolved electronic spectral measurements on a number of systems do appear to show a rapid and then asymptotic convergence, so that nearly all the shift is recovered by n = 30-50. We discuss here a set of examples - B·(N2)n, B·Arn, and Al·Arn (B = benzene) - in which far from bulk shifts are observed even though apparent asymptotes have been reached. Several models are proposed to explain this effect, and their liabilities are discussed.
ASJC Scopus subject areas
- Physical and Theoretical Chemistry