Determination of the threefold internal rotation barrier in ArNH 3
Determination of the threefold internal rotation barrier in ArNH 3
复制标题
ArNH 3 中三重内旋势垒的测定
DOI：
10.1063/1.466489
复制
发表时间：
1994
影响因子：
4.4
通讯作者：
K. Leopold
中科院分区：
文献类型：
--
作者：
A. Grushow;W. Burns;S. Reeve;M. A. Dvorak;K. Leopold
用可调谐远红外差频微波边带光谱法观察了与j=2, k=±1氨相关的弱结合配合物Ar-NH3的2个Σ和4个Π态。结果与已发表的数据相结合，确定了系统的一个新的角势能面。在配合物中，NH3围绕其C3轴进行三次内旋的势垒估计为25.606(24)cm−1，接近最小能量（T形）构型。在两种对称的顶部构型下，势也表现出最大值，能量分别约为53和31 cm−1，高于全局最小值。对称和反对称Σ态之间的位置和分裂表明了与另一对未观察到的态的强相互作用，最有可能是建立在j=1, k=±1 Ar-NH3上的第一个激发分子间拉伸。
The two Σ and four Π states of the weakly bound complex Ar–NH3 correlating to j=2, k=±1 ammonia have been observed by tunable far infrared difference frequency‐microwave sideband spectroscopy. The results have been combined with published data to determine a new angular potential energy surface for the system. The barrier to threefold internal rotation of the NH3 about its C3 axis in the complex is estimated to be 25.606(24) cm−1 near the minimum energy (T‐shaped) configuration. The potential also exhibits maxima at both symmetric top configurations, with energies approximately 53 and 31 cm−1, respectively above that of the global minimum. The location and splitting between the symmetric and antisymmetric Σ states are indicative of a strong interaction with another pair of unobserved states, most likely the first excited intermolecular stretch built on j=1, k=±1 Ar–NH3.