Reactions of laser-ablated Cr atoms with O2 gave a very strong, sharp 965.4 cm−1 band and weak, sharp 1869.7, 984.3, 914.4, 846.3, 716.2, and 643.1 cm−1 bands. The 1869.7, 965.4, and 914.4 cm−1 bands track together on annealing, show 52Cr, 53Cr, 54Cr isotopic splittings appropriate for a single Cr atom and triplets with statistical 16,18O2 for two equivalent O atoms, and are assigned to the ν1+ν3, ν3 and ν1 modes of the bent (128°±4°) chromium dioxide OCrO molecule. The 984.3 cm−1 band shows chromium isotopic splittings for two Cr atoms and 16,18O2 components for two O atoms, and is attributed to the bent CrOCrO molecule. The weak 846.3 cm−1 band exhibits proper oxygen isotopic behavior for CrO and is redshifted 39 cm−1 from the gas-phase value, the maximum shift observed for a first row transition metal monoxide. The sharp 716.2 and 643.1 cm−1 bands track together; the former reveals Cr isotopic splittings for two Cr atoms and the latter 16,18O2 splittings for two sets of dioxygen subunits; the branched-puckered-ring dimer O(Cr2O2)O is identified. Annealing produces new bands due to CrOO, CrO3, Cr(OO)2 and the ring dimers (Cr2O2) and (Cr2O2)O, which are identified from isotopic shifts and splitting patterns.

Laser-ablated V atoms react with O2 to give primarily the bent VO2 dioxide molecule and a smaller yield of the monoxide VO. The OVO valence angle is estimated as 118 ± 3° from oxygen isotopic ν3 frequencies and 121° from DFT calculations. New absorptions appear on annealing to 35 K that can be assigned to two V2O2 isomers and the superoxo adduct to VO2, namely the OOVO2 molecule. Both VO2 and OOVO2 reveal weak ν1 + ν3 combination bands, which support the assignment of ν1 and ν3 fundamental vibrations.

Laser-ablated V, Cr, and Mn atoms mixed with Ar/N2 and pure N2 during condensation at 6−10 K produced and trapped the VN, CrN, and MnN molecules and their dinitrogen complexes. The M−N vibrations were characterized by nitrogen 14/15 isotopic ratios. Stepwise annealing converted the MN molecules into (NN) x MN complexes. The NCrN molecule was identified from nitrogen-14,15 and chromium-52,53,54 isotopic spectra. In addition to end-bonded M(NN) x complexes in the 2200−1900 cm-1 region, evidence for side-bonded M(N2) complexes was found in the 1900−1700 cm-1 region. Density functional calculations provide support for the vibrational assignments.

Platinum and palladium atoms produced by laser ablation were reacted with dioxygen diluted in argon during condensation at 10 K. Reaction products, including the M(O2) and (O2)M(O2) complexes prepared with thermal metal atoms, and the platinum oxides PtO, OPtO, PtO3, OOPtO, and (O2)PtO, were analyzed by matrix infrared spectroscopy. Absorptions due to PdO and OPdO were not identified. Density functional theory (B3LYP) calculations were performed on product molecules, which were identified on the basis of isotopic frequency shifts and correlation with density functional calculations. The most interesting new molecule produced here, linear OPtO, can also be produced by photolysis of the cyclic Pt(O2) complex.

Laser-ablated Co and Ni atoms, co-deposited with pure nitrogen at 10 K, gave a strong new 795.3 cm -1 band with cobalt and a 838.8, 836.1 cm -1 isotopic doublet (2.5/1.0) with nickel, which exhibited 14/15 isotopic ratios appropriate for the diatomic CoN and NiN molecules. In solid argon, CoN absorbs at 826.5 cm -1 and gives way on annealing to bands at 795.8 and 792.0 cm -1 , which are due to (NN) x CoN complexes. Density functional theory (DFT) calculations predict quintet and quartet ground states for CoN and NiN, respectively, and frequencies in reasonable agreement with the observed values. Evidence is also presented for the dimetal dinitrides, (CoN) 2 and (NiN) 2 , with rhombus structures and metal-metal bonding across the ring. DFTbased calculations and revised assignments are presented for Ni-NN stretching modes in the dinitrogen complexes.