Paris Chiara, Alcamí Manuel, Martín Fernando, Díaz-Tendero Sergio
Departamento de Química, Módulo 13, Universidad Autónoma de Madrid, 28049 Madrid, Spain.
J Chem Phys. 2014 May 28;140(20):204307. doi: 10.1063/1.4875805.
In this work, we present a density functional theory study of the structure and stability of neutral and positively-charged coronene C24H12(q+). In particular, we have investigated (i) adiabatic and vertical ionization potentials up to charge q = 9, (ii) the corresponding infrared spectra, and (iii) dissociation energies and potential energy surfaces for several hydrogen loss channels: sequential H+H, H+H(+), H(+)+H, H(+)+H(+), and direct H2 and H2(+). We have found that the stability of positively-charged coronene is extremely high as a consequence of the molecule's capability to redistribute the charge all over the structure. The computed dissociation energies and fragmentation barriers show that there is competition between different hydrogen loss channels and that the relative importance of these channels depends on the charge of the molecule. From a careful analysis of the potential energy surface we conclude that the channel with the lowest barrier corresponds to the loss of H2 from neutral, singly-, doubly-, and triply-charged coronene, H2(+) from quadruply-charged coronene and H(+)+H(+) from quintuply-charged coronene.
在这项工作中，我们对中性和带正电荷的蔻（C24H12(q+)）的结构和稳定性进行了密度泛函理论研究。具体而言，我们研究了：（i）电荷q高达9时的绝热电离势和垂直电离势；（ii）相应的红外光谱；（iii）几个氢损失通道的解离能和势能面，这些通道包括：依次的H+H、H+H(+)、H(+)+H、H(+)+H(+)，以及直接的H2和H2(+)。我们发现，由于分子能够在整个结构中重新分配电荷，带正电荷的蔻具有极高的稳定性。计算得到的解离能和裂解势垒表明，不同氢损失通道之间存在竞争，且这些通道的相对重要性取决于分子的电荷。通过对势能面的仔细分析，我们得出结论，势垒最低的通道对应于从中性、单电荷、双电荷和三电荷蔻中损失H2，从四电荷蔻中损失H2(+)，以及从五电荷蔻中损失H(+)+H(+)。
