A multilayer MCTDH study on the full dimensional vibronic dynamics of naphthalene and anthracene cations.
A multilayer MCTDH study on the full dimensional vibronic dynamics of naphthalene and anthracene cations.
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DOI：
10.1063/1.4772779
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发表时间：
2013-01
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影响因子：
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通讯作者：
Qingyong Meng;H. Meyer
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文献类型：
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作者：
Qingyong Meng;H. Meyer
采用多层多组态含时Hartree方法，结合多态多模振动耦合哈密顿模型，对6个最低双重态的萘(48D)和菲(66D)自由基阳离子进行了全维量子动力学研究。为了更容易地比较全维和降维的结果，MCTDH模拟基于更大规模的基函数和单粒子函数，而不是以前的模拟[S.Gamta，V.S.Reddy，和S.Mahapatra，Phys.化学。化学。太棒了。13,14531(2011年)]，也被执行。为了找到波函数的适当的ML分离(所谓的ML树)，进行了广泛的ML-MCTDH测试计算，并仔细检查了动力学计算的收敛。ML-MCTDH方法是为了有效地模拟大系统的量子动力学而发展起来的，实际上，与相应的降维MCTDH模拟相比，全维ML-MCTDH计算节省了相当多的CPU时间。在已有的全维和降维模拟的基础上，模拟了这两种阳离子的光电子能谱，并与相应的实验光谱进行了比较。PE谱的理论值与实验值吻合较好。全维和降维模拟都给出了PE谱中的所有主要谱带。ML-MCTDH和MCTDH计算得到的振动能级位置与相应的实验结果一致。这些量子动力学研究也补充了天文学家和实验室实验者对波长为~7088、~6707、~6490、~6120和~5959的星际漫射带的观测结果。
Employing the multilayer multiconfiguration time-dependent Hartree (ML-MCTDH) method in conjunction with the multistate multimode vibronic coupling Hamiltonian model, we perform a full dimensional quantum dynamical study on the naphthalene (48D) and anthracene (66D) radical cations in their six lowest-lying doublet electronic states. For easily comparing results of full and reduced dimensionalities, MCTDH simulations based on larger sizes of primitive basis functions and single-particle functions than the previous ones [S. Ghanta, V. S. Reddy, and S. Mahapatra, Phys. Chem. Chem. Phys. 13, 14531 (2011)], are also performed. Extensive ML-MCTDH test calculations are performed to find appropriate ML separations of the wave functions (so-called ML-trees), and the convergence of the dynamical calculations are carefully checked. The ML-MCTDH method was developed for efficiently simulating quantum dynamics of large systems, and in fact the full dimensional ML-MCTDH calculations save a considerable amount of CPU-time in comparison with corresponding reduced dimensional MCTDH simulations. On basis of the present full and reduced dimensional simulations, the photoelectron (PE) spectra of these two cations are simulated and compared with corresponding experimental spectra. The agreement between theoretical and experimental PE spectra is good. Both full and reduced dimensional simulations give all main bands in the PE spectra. The vibronic energy-level positions from both ML-MCTDH and MCTDH calculations agree with corresponding experimental results. These quantum dynamical studies also complement the observations on diffuse interstellar bands with the wavelength of ~7088, ~6707, ~6490, ~6120, and ~5959 Å measured by astronomers as well as laboratory experimentalists.