Spectroscopic Properties and Potential Energy Curves for 30 Electronic States of ReH

✍ Scribed by D.G. Dai; K. Balasubramanian

• Publisher: Elsevier Science
• Year: 1993
• Tongue: English
• Weight: 574 KB
• Volume: 158
• Category: Article
• ISSN: 0022-2852
• DOI: 10.1006/jmsp.1993.1089

✦ Synopsis

Spectroscopic constants and potential energy curves of 30 electronic states of the diatomic (\mathrm{ReH}) are computed using complete active space multiconfiguration self-consistent field followed by first-order configuration interaction (CI) and multireference singles + doubles (\mathrm{CI}) calculations. The second-order CI calculations are made on four low-lying electronic states ( (T_{\mathrm{e}}<10000) (\mathrm{cm}^{-1}) ). We also carry out relativistic (\mathrm{Cl}) calculations including spin-orbit coupling to compute spin-orbit effects on the low-lying states of (\mathrm{ReH}). The ground state of (\mathrm{ReH}) is found to be of ({ }^{\prime} \Sigma^{+}) symmetry (\left(R_{e}=1.82 \AA \AA, \omega_{e}=1611 \mathrm{~cm}^{-1}, D_{\varepsilon}=1.3 \mathrm{eV}\right)) with a very low-lying excited state of ({ }^{5} \Sigma^{+}) symmetry (\left(T_{e} \sim 3000 \mathrm{~cm}^{-1}\right)) in the absence of spin-orbit effects. The analysis of the wavefunctions and Mulliken populations reveals that all the low-lying electronic states of ReH are very ionic (\left(\mathrm{Re}^{+} \mathrm{H}^{-}\right)). The (\mathrm{Re}) atom has an effective configuration of (6 s^{1.15} 6 p^{0.40} 5 d^{5.01}) and (6 s^{1.79} 6 p^{0.06} 5 d^{5.09}) in the ({ }^{7} \mathbf{\Sigma}^{+})and ({ }^{5} \Sigma^{+})states. respectively. The (\operatorname{Re}-\mathrm{H} \sigma) bond in the ({ }^{7} \mathbf{\Sigma}^{+})ground state has (45 % \operatorname{Re}(s)). (16 % \operatorname{Re}(p)), and (39 % \operatorname{Re}(d)) character while in the ({ }^{5}{ }^{+}+)state, it has (60 % \operatorname{Re}(s) .2 % \operatorname{Re}(p)). and (38 % \operatorname{Re}(d)) character. ć. 1993 Academic Press. Inc.