Study of coupled states for the (4s^{2})^{1}S + (4s4p)^{3}P asymptote of Ca_{2}

Abstract

The coupled states A^{1}Σ_{u}^{+} (^{1}D +}1}S), c^{3}Π_{u} (^{3}P + ^{1}S) and a^{3}Σ_{u}^{+} (^{3}P +}1}S) of the calcium dimer are investigated in a laser induced fluorescence experiment combined with high-resolution Fourier-transform spectroscopy. A global deperturbation analysis of the observed levels, considering a model, which is complete within the subspace of relevant neighboring states, is performed using the Fourier Grid Hamiltonian method. We determine the potential energy curve of the A^{1}Σ_{u}^{+} and c^{3}Π_{u} states and the strengths of the couplings between them. The c^{3}Π_{u} and \as states are of particular importance for the description of collisional processes between calcium atoms in the ground state ^{1}S_{0} and excited state ^{3}P_{1} applied in studies for establishing an optical frequency standard with Ca.