Matrix isolation ESR and theoretical studies of metal phosphides.

ABSTRACT

The ZnP, (67)ZnP, CdP, (111)CdP, and (113)CdP radicals have been formed by laser ablation of the metal with GaP pressed into the metal surface, isolated in an inert neon matrix at 4.3 K and their electronic structure was established using electron spin resonance spectroscopy. The following magnetic parameters were determined experimentally for ZnP/(67)ZnP, g(⊥)=1.9982(2), A(⊥)(P)=111(6) MHz, A(⊥)((67)Zn)=160(2) MHz, and D=-29 988(3) MHz and estimates were made for the following ZnP/(67)ZnP magnetic parameters g(∥)=1.9941(2), A(∥)(P)=-5(6) MHz, and A(∥)((67)Zn)=180(50) MHz. The following magnetic parameters for CdP/(111)CdP/(113)CdP were determined experimentally g(⊥)=1.9963(2), A(⊥)(P)=97(3) MHz, A(⊥)((111)Cd)=862(3) MHz, and A(⊥)((113)Cd)=902(3) MHz. Evidence for the formation of the MgP radical was also obtained and an approximate hyperfine coupling constant of A(⊥)(P)=157(6) MHz was determined. The low-lying electronic states of ZnP and MgP were also investigated using the multiconfigurational self-consistent field technique. Potential energy surfaces, binding energies, optimized bond lengths, energy separations, and dissociation energies have been determined. Both radicals are found to have (4)Σ(-) ground states with a leading configuration at r(e) of 10σ(2)11σ(2)5π(1)5π(1)12σ(1) for ZnP and 7σ(2)8σ(2)3π(1)3π(1)9σ(1) for MgP. Significant mixing to this state is calculated for MgP.