Structures and electron detachment energies of AlP2− and Al2P2−

Equilibrium geometries, harmonic vibrational frequencies and electron detachment energies are reported for AlP2− and Al2P2−. The adiabatic electron affinity of AlP2 is calculated to be 1.92 eV at the CCSD(T) level. The 2A1 and 2B1 lowest excited states of AlP2 are located at 0.41 eV and 2.53 eV, respectively, above the 2B2 ground state. The Al2P2− anion has a distorted tetrahedron geometry (2B1–C2ν) and the adiabatic electron affinity of Al2P2 (1Ag–D2h) is computed to be 1.83 eV at the CCSD(T) level. Electron detachment processes from the 2B1–C2ν ground state of Al2P2− to neutral states of Al2P2 are presented and discussed.