The potential energy surface of excited singlet states of BCl by using the equation-of-motion coupled-cluster theory

The excited singlet states of BCl are studied by using the equation-of-motion coupled-cluster singles and doubles theoretical method. The potential energy surfaces (PES) are constructed and the vibrational levels are calculated by using the Fourier-grid-Hamiltonian method. It is shown that D 1Σ+ and E 1Σ+ states correspond to the two stationary points of the same adiabatic PES with double minima. New high-lying four 1Σ, three 1Π, two 1Δ, and one 1Φ excited state are tentatively assigned, and their spectroscopic constants are also derived.