Theoretical investigation of the infrared spectra of the H5(+) and D5(+) cations.
Theoretical investigation of the infrared spectra of the H5(+) and D5(+) cations.
复制标题
H5( ) 和 D5( ) 阳离子红外光谱的理论研究。
DOI：
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发表时间：
2013
影响因子：
2.9
通讯作者：
R. Prosmiti
中科院分区：
文献类型：
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作者：
Á. Valdés;R. Prosmiti
本文报道了H5（+）和D5（+）团簇在低能区（300-2200 cm（-1））和高能区（2400-4500 cm（-1））的红外光谱的降维量子动力学计算。所提出的四维量子模型描述了质子在两个振动氢分子之间的运动。在多组态时间相关Hartree方法中使用时间相关和时间无关方法进行模拟。波包的传播包括一个吸收方案来处理振动离解态，并分配不同的谱线，块改进的松弛计算进行绑定和predissociative振动态的系统。报告的计算利用分析从头计算为基础的势能，和“在飞”DFT偶极矩表面。光谱中的主要特征被归因于共享质子伸缩模的激发，并且在解离之上还涉及两个H2的对称和反对称伸缩以及H3（+）的呼吸模。计算的两种阳离子的红外吸收光谱是在最近的实验测量，可从多光子解离和质量选择的单光子光解离光谱技术非常好的协议。本结果与以前的理论计算这些系统的比较。不同的理论方法和实验测量之间的这种比较可以用来评估所采用的近似，并指导高阶计算。
Reduced dimensional quantum dynamics calculations of the infrared spectrum of the H5(+) and D5(+) clusters are reported in both low, 300–2200 cm(–1), and high, 2400–4500 cm(–1), energy regions. The proposed four-dimensional quantum model describes the motion of the proton between the two vibrating hydrogen molecules. The simulations are performed using time-dependent and time-independent approaches within the multiconfiguration time-dependent Hartree method. Propagation of the wavepackets includes an absorbing scheme to deal with vibrational dissociating states, and to assign the different spectral lines, block improved relaxation computations are performed for both bound and predissociative vibrational states of the systems. The reported computations make use of an analytical ab initio-based potential energy, and “on the fly” DFT dipole moment surfaces. The predominant features in the spectra are assigned to the excitations of the shared-proton stretch mode, and above dissociation the symmetric and antisymmetric stretching of the two H2 and the breathing mode of H3(+) are also involved. The computed infrared absorption spectra for both cations are in very good agreement with the recent experimental measurements available from multiple-photon dissociation and mass-selected single-photon photodissociation spectroscopy techniques. Comparison of the present results with previous theoretical calculations on these systems is also presented. Such comparisons between different theoretical approaches and experimental measurements can serve to evaluate the approximations employed, and to guide higher-order computations.