Photoelectron spectroscopy of coordinatively unsaturated organometallic anions can provide a means to probe the ground and low lying excited states of the corresponding neutral radicals. We report results for the early 3d transition metal monocarbonyls VCO and CrCO, and for the late metal complexes FeCO, CoCO and NiCO. Each spectrum displays a transition to the ground state of the neutral complex, and to an excited state whose spin multiplicity differs by two from that of the ground state. For a given complex, these states share nominally the same electron configuration but differ in the spin coupling of the metal 4s electron. There is a reversal in the state ordering as one proceeds across the transition series, from a high spin ground state for VCO (6σ+) and CrCO (7σ+) to a low spin ground state for FeCO (3σ-), CoCO (2Δ) and NiCO (1σ+). The measured state splittings and vibrational frequencies provide insight into the factors that determine the ordering and bonding properties of these states. Recent results for the linear H-M-CO isomers of Fe and Co are also reported.
|Original language||English (US)|
|Number of pages||12|
|Journal||Proceedings of SPIE - The International Society for Optical Engineering|
|State||Published - Jun 17 1994|
|Event||Laser Techniques for State-Selected and State-to-State Chemistry II 1994 - Los Angeles, United States|
Duration: Jan 23 1994 → Jan 29 1994
Bibliographical noteFunding Information:
Research grants from the National Science Foundation (P11 CHE-8858373) and from the Exxon Education Foundation are gratefully acknowledged.
Research grants from the National Science Foundation (PYI CHE-8858373) and from the Exxon Education Foundation are gratefully acknowledged.