The vibration-rotation emission spectrum of hot BeF2.
The vibration-rotation emission spectrum of hot BeF2.
复制标题
DOI：
10.1063/1.2039085
复制
发表时间：
2005-10
期刊：
影响因子：
--
通讯作者：
Shanshan Yu;A. Shayesteh;P. Bernath;J. Koput
中科院分区：
文献类型：
--
作者：
Shanshan Yu;A. Shayesteh;P. Bernath;J. Koput
在1000 ℃下的氟化铍蒸气的高分辨率红外发射光谱旋转分析的协助下，使用耦合簇方法，包括单，双激发和微扰包含三重激发，结合相关一致的基础设置，以五重zeta质量的大规模从头计算。对nu 3基本带、nu 1 + nu 2、nu 1 + nu 3和2nu 2 + nu 3组合带以及18条热带进行了归属。对称伸缩（nu 1）、弯曲（nu 2）和反对称伸缩（nu 3）模式频率分别被确定为769.0943（2）、342.6145（3）和1555.0480（1）cm-1，这些频率来自nu 3、nu 1 + nu 3和nu 1 + nu 2带的带源。将观测到的振动项和B转动常数同时拟合到考虑费米共振的有效哈密顿模型中，得到了BeF 2的解扰平衡振动和转动常数.平衡转动常数（Be）为0.235354（41）cm-1，相应的平衡键距（re）为1.3730（1）A.我们的从头计算结果与我们的实验结果非常一致，计算值为1.374 A的平衡键距（re）。与等电子CO2分子一样，BeF 2的费米共振非常强，相互作用常数k122为90.20（4）cm-1。
The high-resolution infrared emission spectrum of BeF2 vapor at 1000 degrees C was rotationally analyzed with the assistance of large-scale ab initio calculations using the coupled-cluster method including single and double excitations and perturbative inclusion of triple excitations, in conjunction with correlation-consistent basis sets up to quintuple-zeta quality. The nu3 fundamental band, the nu1+nu2, nu1+nu3, and 2nu2+nu3 combination bands, and 18 hot bands were assigned. The symmetric stretching (nu1), bending (nu2), and antisymmetric stretching (nu3) mode frequencies were determined to be 769.0943(2), 342.6145(3), and 1555.0480(1) cm-1, respectively, from the band origins of the nu3, nu1+nu3, and nu1+nu2 bands. The observed vibrational term values and B rotational constants were fitted simultaneously to an effective Hamiltonian model with Fermi resonance taken into account, and deperturbed equilibrium vibrational and rotational constants were obtained for BeF2. The equilibrium rotational constant (Be) was determined to be 0.235 354(41) cm-1, and the associated equilibrium bond distance (re) is 1.3730(1) A. The results of our ab initio calculations are in remarkably good agreement with those of our experiment, and the calculated value was 1.374 A for the equilibrium bond distance (re). As in the isoelectronic CO2 molecule, the Fermi resonance in BeF2 is very strong, and the interaction constant k122 was found to be 90.20(4) cm-1.