ISSN:
0192-8651
Keywords:
Computational Chemistry and Molecular Modeling
;
Biochemistry
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
,
Computer Science
Notes:
We present potential energy surfaces for Rh—CO obtained from density functional theory for two electronic states of Rh—CO. We have performed local spin-density calculations including relativistic as well as gradient corrections. The construction of a reasonably accurate atom-atom potential for Rh—CO is not possible. We were much more successful in constructing the potential energy surfaces by representing the potential as a spherical expansion. The expansion coefficients, which are functions of the distance between the rhodium atom and the carbon monoxide center of mass, can be represented by Lennard-Jones, Buckingham, or Morse functions, with an error of the fit within 10 kJ/mol. The potential energy surfaces, using Morse functions, predict that the electronic ground state of Rh—CO is 2Σ+ or 2Δ. This is a linear structure with an equilibrium distance of rhodium to the carbon monoxide center of mass of 0.253 nm. The bonding energy is -184 kJ/mol. Further, Morse functions predict that the first exicted state is 4A′. This is a bent structure (∠Rh—CO = 14°) with an equilibrium distance of rhodium to the carbon monoxide center of mass of 0.298 nm. The bonding energy of this state is -60 kJ/mol. Both these predictions are in good agreement with the actual density functional calculations. We found 0.250 nm with -205 kJ/mol for 2Σ+ and 0.253 nm with -199 kJ/mol for 2Δ. For 4A′, we found 0.271 nm, ∠Rh—CO = 30°, with -63 kJ/mol. The larger deviation for 4A′ than for 2Σ+ or 2Δ is a consequence of the fact that the minimum for 4A′ is a very shallow well. © 1994 by John Wiley & Sons, Inc.
Additional Material:
2 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/jcc.540151002
