Electronic states of Cu+4, Ag+4, and Au+4: Interpretation of the optical spectra of Cu+4

摘要

Complete active space multiconfiguration selfhyphen;consistent field followed by singlehyphen;reference and multihyphen;reference CI calculations which included up to 1.1 million configurations are carried out on Cu+4, Ag+4, and Au+4. The ground states of all three ions are found to beXthinsp;2B1ustates with equilibrium geometries of rhombus. We compute the atomization energies of Cu+4, Ag+4, and Au+4as 6.2, 5.2, and 7.3 eV, respectively, in agreement, with the experimental prediction for AE(Cu+4) 6.8 eV by Jarrold and Creegan. Calculations of excited states reveal a lowhyphen;lying2B2uexcited state (Tesim; 6000ndash;7000cmminus;1) for all three M+4. For Cu+4we also studied the excited2Ag,2B1g, and2B2gstates. Our calculations show that the optical spectra of Cu+4observed by Jarrold and Creegan in the 690 nm region are due to the (Cudrarr;s)2B1gndash;X2B1utransition while one of the unassigned bands in the 420ndash;490 nm region is due to the2Agndash;X2B1utransition of Cu+4which is predominantly a valence transition. Our calculations support the complex vibronic structure of the 690 nm system.