Vibrational effects in the muonated formyl radical MuCO2A′

The muonium and deuterium isotopomers of the formyl radical HCO 2 A′ are investigated using a variation-perturbation approach for the calculation of vibrational effects in these radicals. After inclusion of anharmonicity MuCO has a calculated zero-point vibrational energy of 74.15 kJ mol -1 compared with a value of 36.11 kJ mol -1 for HCO. The effect is discussed of these zero-point energy contributions to the formation of MuCO. The calculated reduced muon–electron hyperfine coupling constant A µ ′ is 437.75±2.86 MHz for the muonated radical in the ground vibrational level. This represents a calculated α-isotope effect A µ ′ /A p of 1.18, where A p is the proton–electron hyperfine coupling constant in the formyl radical.