Theoretische Chemie, Physikalisch-Chemische Institut, Ruprecht-Karls Universität Heidelberg, Im Neuenheimer Feld 229, D-69120 Heidelberg, Germany.
J Chem Phys. 2013 Jan 7;138(1):014313. doi: 10.1063/1.4772779.
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.
采用多层多组态含时哈特ree 方法（ML-MCTDH）结合多态多模振子耦合哈密顿模型，我们对萘（48D）和蒽（66D）自由基阳离子在其六个最低的二重态电子态中进行了全维量子动力学研究。为了方便比较全维和降维的结果，我们还进行了基于比以前更大的基函数和单粒子函数大小的 MCTDH 模拟，[S. Ghanta、V. S. Reddy 和 S. Mahapatra，Phys. Chem. Chem. Phys. 13, 14531 (2011)]。进行了广泛的 ML-MCTDH 测试计算，以找到合适的波函数 ML 分离（所谓的 ML-树），并仔细检查动力学计算的收敛性。ML-MCTDH 方法是为了有效地模拟大系统的量子动力学而开发的，事实上，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。基于目前的全维和降维模拟，我们模拟了这两种阳离子的光电子（PE）谱，并将其与相应的实验谱进行了比较。理论和实验 PE 谱之间的一致性很好。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 计算得出的振子能级位置与相应的实验结果一致。这些量子动力学研究还补充了天文学家测量的波长约为 7088、6707、6490、6120 和 5959 Å 的弥漫星际带的观测结果，以及实验室实验人员的观测结果。
