Magneto-optical studies of silver atoms in neon matrices

Abstract

Abstract Absorption and magnetic circular dichroism measurements have been carried out on silver atoms trapped in neon matrices at cryogenic temperatures. By using the method of moments, it has been possible to show that the degeneracy of the 2 P excited state, obtained from the promotion of an electron from the Ag 5s to the 5p orbital, is lifted under the influence of simultaneous spin–orbit and vibrational coupling with the rare gas cage. From an analysis of the 2 P ← 2 S transition, the 2 P state spin–orbit coupling constant ( λ ) as well as the cubic ( E C ) and noncubic ( E NC ) rare gas cage vibrational mode contributions have been extracted. They are λ = 829 ± 52, E C = 340 ± 54 and E NC = 465 ± 74 cm −1 . The neon matrix has a profound influence on the silver atom spin–orbit coupling constant, increasing it from 614 cm −1 in the gas phase to 829 cm −1 . This large value is in line with the trend previously found for the other rare gas matrices: spin–orbit constant decrease with rare gas atomic mass increase. The trend is: 829 cm −1 (Ag/Ne), 783 cm −1 (Ag/Ar), 638 cm −1 (Ag/Kr), and 583 cm −1 (Ag/Xe). Calculations of the spin–orbit reduction factors using a “supermolecule” model involving the metal atom and the 12 surrounding rare gas atoms mimics the experimental results well, although the predicted value for Ag/Ne is smaller than the observed one by ∼15%. This discrepancy may arise from a slight collapsing of the rare gas cage onto the entrapped silver atom.