ESR spectra of Ag₃(²A₁) in an N₂ matrix

ESR spectra assigned to Ag₃ molecules have been produced by codepositing atomic silver with excess nitrogen at temperatures close to 4.2 K. The spectra are characterized by an axially symmetric spin Hamiltonian having g_∥ =1.9933(3) and g_⊥ =1.9558(3) and, for ¹⁰⁷Ag₃, A_∥(1) =310.8(6) G with A_⊥(1) =310.1(6) G and A_∥(2) =76.0(2) G with A_⊥(2) =72.6(2) G for the apical(1) and basal(2) nuclei, respectively. The axial symmetry of the spectra is believed to imply that the trimer is rotating about one axis. There is no evidence for a pseudorotating trimer spectrum. The isotropic spin populations are ρ_5s(1) =0.51 and ρ_5s(2) =0.12 implying an acute angled geometry with ground state symmetry ²A₁. This is in sharp contrast to the obtuse angled isomer (²B₂ ground state) found for Ag₃ in a C₆D₆ matrix. For Ag₃(²A₁) there is little p character on the apical atom but a 10%–15% p hybridization on each of the two basal nuclei.