Potential energy surfaces of eight low-lying electronic states of Rh sub 3
- Department of Chemistry, Arizona State University, Tempe, Arizona 85287-1604 (USA)
Complete active space multiconfiguration self-consistent-field (CASSCF) followed by multireference singles plus doubles configuration-interaction (MRSDCI) calculations which include 27 active electrons are carried out on eight low-lying electronic states of Rh{sub 3}. The MRSDCI calculations included up to 2.3 million configurations. The spin-orbit effects are included by using the relativistic configuration-interaction (RCI) method. All the low-lying states considered here lie within 0.20 eV. All the doublet states are Jahn--Teller components of the doubly degenerate {sup 2}{ital E}{prime} and {sup 2}{ital E}{double prime} states in equilateral triangular geometry ({ital D}{sub 3}{sub {ital h}}), while the quartet states arise from the Jahn--Teller components of {sup 4}{ital E}{prime} and {sup 4}{ital E}{double prime} states. The splittings between the two Jahn--Teller components of both the {sup 2}{ital E}{prime} and {sup 2}{ital E}{double prime} states, which yield barriers to pseudorotation, are 3.9 kcal/mol. The lowest-lying {sup 2}{ital A}{sub 2} and {sup 2}{ital A}{sub 1} states are separated only by 0.03 eV. Thus, low-lying electronic states of Rh{sub 3} are best described using a dynamic Jahn--Teller model. The Mulliken population analyses of the MRSDCI natural orbitals reveal the larger {ital s} population of the apex atom of the isosceles triangle in comparison to the base atoms. The base atoms have larger {ital d} populations for all electronic states. The present calculations also reveal a considerable mixing among the 4{ital d}{sup 8}5{ital s}{sup 1}, 4{ital d}{sup 9}, and 4{ital d}{sup 8}5{ital p}{sup 1} configurations of the rhodium atom. The atomization energy of Rh{sub 3} is calculated as 188 kcal/mol. The trimer (Rh{sub 3}) is predicted to be considerably more stable than the dimer (Rh{sub 2}).
- DOE Contract Number:
- FG02-86ER13558
- OSTI ID:
- 7022069
- Journal Information:
- Journal of Chemical Physics; (USA), Vol. 93:1; ISSN 0021-9606
- Country of Publication:
- United States
- Language:
- English
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