GeS分子基态和低激发态的势能曲线与光谱性质

本文以aug-cc-pv5Z为基组, 采用考虑Davidson修正的多参考组态相互作用方法(MRCI+Q)得到了GeS分子基态(X¹Σ⁺)和5个低激发态(1¹Σ, 1¹Δ, A¹Π, 1⁵Σ⁺, 2⁵Σ⁺)的势能曲线. 计算结果表明: 2⁵Σ⁺态为排斥态, 其余5个态为束缚态; 6个态有着共同的离解通道, 离解极限均为Ge(³P)+S(³P). 利用计算得到的势能曲线得了X¹Σ⁺, 1¹Σ^-, 1¹Δ, A¹Π和1⁵Σ⁺态的垂直跃迁能T_e, 平衡键长R_e, 离解能D_e, 谐振频率ω_e, 非谐性常数ω_ex_e及平衡位置的电偶极矩. X¹Σ⁺态的R_e 为2.034 Å, D_e 为5.728 eV, ω_e为571.73 cm^-1, ω_ex_e为1.6816 cm^-1, 平衡位置的电偶极矩为1.9593 Debye. 激发态1¹Σ, 1¹Δ, A¹Π, 1⁵Σ⁺的T_e 依次为25904.81, 26209.22, 32601.19, 43770.26 cm^-1; R_e依次为2.313, 2.322, 2.188, 2.8790 Å; D_e依次为2.524, 2.487, 1.694, 0.3036 eV, ω_e依次为358.90, 353.08, 376.32, 134.96 cm^-1; ω_ex_e依次为1.2421, 1.2151, 1.6608, 1.9095 cm^-1; 平衡位置的电偶极矩依次为1.3178, 1.4719, 1.5917, -1.9785 Debye. 通过求解核运动的薛定谔方程得到了J=0时X¹Σ⁺, 1¹Σ^-, 1¹Δ, A¹Π和1⁵Σ⁺态前30个振动态的振动能级G_v和分子常数B_v, 得到的结果和已有的实验值及其他理论值符合较好.

Potential energy curves and spectroscopic properties of GeS molecules: in ground states and low-lying excited states

The potential energy curves (PECs) for ground state (X¹Σ⁺) and five low-lying electronic states (1¹Σ^-, 1¹Δ, A¹Π, 1⁵Σ⁺, 2⁵Σ⁺) of the GeS molecule have been studied by multi-reference configuration interaction (MRCI) plus Davidson correction (+Q) with all-electron basis set aug-cc-pv5Z. Results show that the 2⁵Σ⁺ state is an unstable repulsive state, and the others are bound states, and the six electronic states are dissociated along the same channel, Ge(³P)+S(³P). The adiabatic transition energy T_e equilibrium bond length R_e, dissociation energy D_e, harmonic frequency ω_e, anharmonic constant ω_ex_e, and equilibrium dipole moments are obtained by fitting the PECs for the X¹Σ⁺, 1¹Σ^-, 1¹Δ, A¹Π and 1⁵Σ⁺ states. While R_e is 2.034 Å, D_e 5.728 eV, ω_e 571.73 cm^-1, ω_ex_e 1.6816 cm^-1, the equilibrium dipole moment is 1.9593 Debye for the ground state. The values of T_e are 25904.81, 26209.22, 32601.19, 43770.26 cm^-1 for 1¹Σ, 1¹Δ, A¹Π and 1⁵Σ⁺ states, respectively; the values of R_e are 2.313, 2.322, 2.188, 2.8790 Å for 1¹Σ, 1¹Δ, A¹Π and 1⁵Σ⁺ states, respectively; the values of D_e are 2.524, 2.487, 1.694, 0.3036 eV for 1¹Σ^-, 1¹Δ, A¹Π and 1⁵Σ⁺ states, respectively; the values of ω_e are 358.90, 353.08, 376.32, 134.96 cm^-1 for 1¹Σ^-, 1¹Δ, A¹Π and 1⁵Σ⁺ states, respectively; the values of ω_ex_e are 1.2421, 1.2151, 1.6608, 1.9095 cm^-1 for 1¹Σ, 1¹Δ, A¹Π and 1⁵Σ⁺ states, respectively, and the values of equilibrium dipole moments are 1.3178, 1.4719, 1.5917, -1.9785 Debye for 1¹Σ^-, 1¹Δ, A¹Π and 1⁵Σ⁺ states, respectively. By solving the radial Schrödinger equation of nuclear motion, the 30 vibration levels and 30 inertial rotation constants (J=0) for X¹Σ⁺, 1¹Σ^-, 1¹Δ, A¹Π and 1⁵Σ⁺ states are also obtained, and all of are in good agreement with the available experimental and other theoretical values.