Chemistry Department, Shelby Hall, The University of Alabama, Shelby Hall, Box 870336, Tuscaloosa, Alabama 35487-0336, USA.
J Phys Chem A. 2010 Sep 2;114(34):9349-58. doi: 10.1021/jp1050657.
Geometry parameters, frequencies, heats of formation, and bond dissociation energies are predicted for the simple alkaline earth (Be, Mg and Ca) fluorides, chlorides, oxides, and hydroxides at the coupled cluster theory [CCSD(T)] level including core-valence correlation with the aug-cc-pwCVnZ basis sets up to n = 5 in some cases. Additional corrections (scalar relativistic effects, vibrational zero-point energies, and atomic spin-orbit effects) were necessary to accurately calculate the total atomization energies and heats of formation. The calculated geometry parameters, frequencies, heats of formation, and bond dissociation energies are compared with the available experimental data. For a number of these alkaline earth compounds, the experimental geometries and energies are not reliable. MgF(2) and BeF(2) are predicted to be linear and CaF(2) is predicted to be bent. BeOH is predicted to be bent, whereas MgOH and CaOH are linear. The OBeO angle in Be(OH)(2) is not linear, and the molecule has C(2) symmetry. The heat of formation at 298 K for MgO is calculated to be 32.3 kcal/mol, and the bond dissociation energy at 0 K is predicted to be 61.5 kcal/mol.
对于简单的碱土金属（Be、Mg 和 Ca）氟化物、氯化物、氧化物和氢氧化物，在耦合簇理论 [CCSD(T)] 水平上预测了几何参数、频率、生成热和键离解能，包括在某些情况下高达 n = 5 的核价相关与 aug-cc-pwCVnZ 基组。为了准确计算总原子化能和生成热，需要进行额外的修正（标量相对论效应、振动零点能和原子自旋轨道效应）。计算出的几何参数、频率、生成热和键离解能与可用的实验数据进行了比较。对于这些碱土金属化合物中的许多化合物，实验几何形状和能量并不可靠。预测 MgF(2) 和 BeF(2) 为线性，CaF(2) 为弯曲。预测 BeOH 为弯曲，而 MgOH 和 CaOH 为线性。在 Be(OH)(2) 中，OBeO 角不是线性的，分子具有 C(2) 对称性。MgO 在 298 K 时的生成热计算为 32.3 kcal/mol，0 K 时的键离解能预测为 61.5 kcal/mol。
