A theoretical study on low-lying electronic states and spectroscopic properties of PH

The low-lying electronic states (X(3)∑(-), a(1)Δ, b(1)Σ(+), A(3)Π, c(1)Π and (5)∑(-)) of the PH species correlating with the first three dissociation channels have been investigated at the MRCI+Q/aug-cc-PV5Z level of theory. Accurate adiabatic potential energy curves and spectroscopic constants (T(e), R(e), ω(e)χ(e), ω(e), B(e), D(e)) of these electronic states have been reported. Effect of the spin-orbit coupling on the A(3)Π and (5)∑(-) states of the PH has been calculated, which lead to the spin-orbit-induced predissociation of the A(3)Π state. Electronic transition moment, Einstein coefficients and Franck-Condon factors for the A(3)Π - X(3)∑(-) system have been calculated. Dipole moment functions (μ(e)) and radiative lifetime (τ(v')) for the A(3)Π state has also been determined. The radiative lifetime for A(3)Π - X(3)∑(-) transition is computed and compared with the available data.