AN ABINITIO STUDY OF THE LOW-LYING DOUBLET STATES OF AGO AND AGS

Spectroscopic constants (Do, re, μe, Te) are determined for the doublet states of AgO and AgS below ≈ 30000 cm-1. valence basis sets are employed in conjunction with relativistic effective core potentials (RECPs). Electron correlation is included using the modified coupled-pair functional (MCPF) and multireferenceconfiguration interaction (MRCI) methods. The A 2Σ+-X 2Π band system is found to occur in the near infrared ( ≈ 9000 cm-1) and to be relatively weak with a radiative lifetime of 900 μs for A 2Σ+ (ν = 0). The weakly bound C 2Π state (our notation), the upper state of the blue system, is found to require high levels of theoretical treatment to determine a quantitatively accurate potential. The red system is assigned as a transition from the C 2Π state to the previously unobserved A 2Σ+ state. Several additional transitions are identified that should be detectable experiment A more limited study is performed for the vertical excitation spectrum of AgS. In addition, a detailed all-electron study of the X 2Π and A 2Σ+ states of AgO is carried out using large atomic natural orbital (ANO) basis sets. Our best calculated Do value for AgO is significantly less than the experimental value, which suggests that there may be some systematic error in the experimental determination. © 1990.