Reactions of laser-ablated uranium atoms, cations, and electrons with O2 during condensation with excess neon produce UO, UO2, UO3, UO2 +, and UO2 - as characterized by infrared spectra with oxygen isotopic substitution and B3LYP/pseudopotential calculations. Differences in low-lying states for UO2 give rise to substantial shifts and ground state reversal between argon and neon matrices. A series of B3LYP/pseudopotential calculations has been undertaken on oxide species related to the uranyl dication by the addition of one, two, or three electrons. Several electronic states have been characterized for each species. These simple, low-cost calculations predict vibrational frequencies which match those observed in neon matrices extremely well (typically 3−5% too high). The ground state of neutral UO2 appears to have 3Φu symmetry, while 2Φu ground states are implied for UO2 + and UO2 -.

Laser-ablated Ni atoms and electrons react with CO in excess argon during condensation to form the Ni(CO)1 - 4 complexes and Ni(CO)1 - 3 - anions. Matrix infrared spectra of the neutral complexes with 12C16O, 13C16O, and 12C18O substitution are in agreement with earlier reports with thermal Ni atoms. In addition, new absorptions at 1847.0, 1801.7, and 1858.8 cm-1 exhibit isotopic spectra in excellent agreement with DFT calculations for the Ni(CO)1 - 3 - anions. An experiment doped with the CCl4 electron-trapping molecule gave the same Ni(CO)1 - 4 spectrum without the corresponding anions, which strongly supports this identification of the molecular anions.

Laser ablated niobium and tantalum atoms have been reacted with CO molecules during condensation in excess neon. The Nb(CO) x and Ta(CO) x (x = 1−6) carbonyls formed during sample deposition or on annealing are the major products. The novel CNbO carbide−oxide molecule was produced on visible photolysis via isomerization of the NbCO carbonyl. The ONbCCO and OTaCCO molecules were formed by near-UV−vis photon-induced rearrangement of the Nb(CO)2 and Ta(CO)2 dicarbonyls and further rearrange to the (C2)NbO2 and (C2)TaO2 molecules on UV photolysis. Evidence is also presented for the CNbO-, CTaO-, Nb(CO) x -, and Ta(CO) x - anions. The product absorptions were identified by isotopic substitution (13C16O, 12C18O, and mixtures), electron trapping with added CCl4, and density functional calculations of isotopic frequencies.

Laser-ablated gallium atoms react with nitrogen atoms and molecules to give GaN, NGaN, Ga 3 N, and GaN 3 , which are identified from nitrogen and gallium isotopic shifts, mixed isotopic splittings, and density functional theory calculations. A 484.9 cm -1 band is assigned to the GaN molecule perturbed by the nitrogen matrix, sharp 586.4 and 584.1 cm -1 bands to the antisymmetric vibration of the linear N 69 GaN and N 71 GaN molecules, 666.2 and 656.0 cm -1 bands to the planar Ga 3 N molecule, and 2096.9 and 1328.3 cm -1 bands to antisymmetric and symmetric N-N-N vibrations of the GaNNN azide molecule. This work provides the first experimental evidence for Ga x N y molecules that may be involved in semiconductor film growth. Laser-ablated In and Tl atom reactions produce analogous molecules.

Laser-ablated thorium atoms have been reacted with CO molecules during condensation in excess neon. Absorptions at 617.7 and 812.2 cm(-1) are assigned to Th-C and Th-O stretching vibrations of the CThO molecule. Absorptions at 2048.6, 1353.6, and 822.5 cm(-1) are assigned to the OThCCO molecule, which is formed by CO addition to CThO and photochemical rearrangement of Th(CO)(2). The OThCCO molecule undergoes further photoinduced rearrangement to OTh(eta(3)-CCO), which is characterized by C-C, C-O, and Th-O stretching vibrations at 1810.8, 1139.2, and 831.6 cm(-1). The Th(CO)(n) (n = 1-6) complexes are formed on deposition or on annealing. Evidence is also presented for the CThO(-) and Th(CO)(2)(-) anions, which are formed by electron capture of neutral molecules. Relativistic density functional theory (DFT) calculations of the geometry structures, vibrational frequencies, and infrared intensities strongly support the experimental assignments. It is found that CThO is an unprecedented actinide-containing carbene molecule with a triplet ground state and an unusual bent structure ( angleCThO = 109 degrees ). The OThCCO molecule has a bent structure while its rearranged product OTh(eta(3)-CCO) is found to have a unique exocyclic structure with side-bonded CCO group. We also find that both Th(CO)(2) and Th(CO)(2)(-) are, surprisingly, highly bent, with the angleC-Th-C bond angle being close to 50 degrees; the unusual geometries are the result of extremely strong Th-to-CO back-bonding, which causes significant three-centered bonding among the Th atom and the two C atoms.