Chemistry Department, Faculty of Science, King Saud University, P.O. Box 2455, Riyadh 11451, Kingdom of Saudi Arabia.
J Phys Chem A. 2010 Nov 25;114(46):12258-68. doi: 10.1021/jp105390c. Epub 2010 Oct 29.
Possible structures of the carbon-nitrogen clusters of the form C(m)N(n) (m = 1-4, n = 1-4, m + n = 2-5) were predicted for the neutral, anion, and cation species in the singlet, doublet, and triplet states, whenever appropriate. The calculations were performed at the G3, MP2(fc)/6-311+G*, and B3LYP/6-311+G* levels of theory. Several molecular properties related to the experimental data--such as the electronic energy, equilibrium geometry, binding energy, HOMO-LUMO gap (HLG), and spin contamination <S(2)>--were calculated. In addition the vertical electron attachment, the adiabatic electron affinity, and vertical ionization energy, of the neutral clusters were calculated. Most of the predicted lowest energy structures were linear, whereas bent structures became more stable with the increase of the cluster size and increase of the number of the N atoms. In most of the predicted lowest energy structures, the N atom prefers the terminal position with acetylenic bond. The calculated BE of the predicted clusters increases with the increase of the cluster size for the neutral and cation clusters but decreases with the increase of the cluster size for the anion clusters. The predicted clusters are characterized by high HLG of about 11 eV on the average, with that of the anion clusters is smaller than that for the neutral and cation clusters. It is concluded then that the anion clusters are less stable than the corresponding neutral and cation clusters. Finally, the N(2) loss reaction is treated.
预测了形式为 C(m)N(n) 的碳-氮簇（m = 1-4，n = 1-4，m + n = 2-5）的中性、阴离子和阳离子在单重态、双重态和三重态中的可能结构，在适当的情况下。计算在 G3、MP2(fc)/6-311+G* 和 B3LYP/6-311+G* 理论水平上进行。计算了与实验数据相关的几个分子性质，如电子能量、平衡几何、结合能、最高占据分子轨道-最低未占据分子轨道间隙（HLG）和自旋污染<S(2)>。此外，还计算了中性簇的垂直电子附加、绝热电子亲合能和垂直电离能。预测的最低能量结构大多数为线性，而随着簇尺寸和 N 原子数的增加，弯曲结构变得更加稳定。在预测的最低能量结构中，N 原子优先占据具有炔键的末端位置。对于中性和阳离子簇，预测簇的 BE 随簇尺寸的增加而增加，但对于阴离子簇，BE 随簇尺寸的增加而减小。预测的簇的特点是平均约为 11 eV 的高 HLG，其中阴离子簇的 HLG 小于中性和阳离子簇的 HLG。因此可以得出结论，阴离子簇比相应的中性和阳离子簇不稳定。最后，处理了 N(2) 损失反应。
