The potential energy curves (PECs) for ground electronic state (X1Σ+) and seven excited electronic states (a3Π, A1Π, b3Σ+, c3Σ+, B1Π, C1Σ+, d3Π) of LiAl are obtained using the multi-configuration reference single and double excited configuration interaction method. Equilibrium bond length Re , adiabatic excited energy Te and vertical excited energy Tv are obtained. It is shown that c3Σ+is an unstable repulsive state, A1Π is a weak bound state and the others are all bound states. Predissociation can be found between b3Σ+and c3Σ+states. Eight electronic states are dissociated along two channels, Li(2S)+Al(2P0) and Li(2P0)+Al(2P0). And then PECs are fitted to analytical Murrell-Sorbie potential function to deduce the spectroscopic parameters:the Re is 0.2863 nm,ωe is 316 cm−1 and De is 1.03 eV for the ground state;the values of Tv of excited states are 0.27, 0.83, 1.18, 1.14, 1.62, 1.81 and 2.00 eV;the values of De are 1.03, 0.82 and 0.26, repulsive state, 1.54, 1.10, 0.93 eV, and the values of corresponding frequencyωe are 339, 237, 394, repulsive state, 429, 192, 178 cm−1. By solving the radial Schr¨odinger equation of nuclear motion, the vibration levels, inertial rotation constants (J=0) are reported for the first time.% 利用单双激发多参考组态相互作用方法获得了LiAl分子基态X1Σ+及七个激发态a3Π, A1Π, b3Σ+, c3Σ+, B1Π, C1Σ+, d3Π的势能曲线,通过势能曲线得到各态的平衡核间距Re ,进而求得绝热激发能和垂直激发能.计算结果表明： c3Σ+电子态是一个不稳定的排斥态, A1Π态是一个较弱的束缚态,其余6个电子态均为束缚态；b3Σ+与c3Σ+态之间存在预解离现象；8个电子态分别解离到两个通道,即Li(2S)+Al(2P0)与Li(2P0)+Al(2P0).接着将势能曲线拟合到Murrel-Sorbie解析势能函数形式,据此获得各态的光谱数据：基态X1Σ+的平衡键长为0.2863 nm,谐振频率为316 cm−1,解离能De 为1.03 eV；激发态a3Π, A1Π, b3Σ+, c3Σ+, B1Π, C1Σ+, d3Π的垂直激发能依次为0.27,0.83,1.18,1.14,1.62,1.81,2.00 eV；解离能依次为1.03,0.82,0.26,排斥态,1.54,1.10,0.93 eV,相应谐振频率ωe为339,237,394,排斥态,429,192,178 cm−1.通过求解核运动的薛定谔方程找到了J=0时LiAl分子7个束缚电子态的振动能级和转动惯量.
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