Multimode quantum dynamics using Gaussian wavepackets: The Gaussian-based multiconfiguration time-dependent Hartree (G-MCTDH) method applied to the absorption spectrum of pyrazine
Multimode quantum dynamics using Gaussian wavepackets: The Gaussian-based multiconfiguration time-dependent Hartree (G-MCTDH) method applied to the absorption spectrum of pyrazine
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DOI：
10.1063/1.2996349
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发表时间：
2008-11-07
影响因子：
4.4
通讯作者：
Worth, G. A.
中科院分区：
文献类型：
--
作者：
Burghardt, I.;Giri, K.;Worth, G. A.
采用基于高斯的多组态含时Hartree（G-MCTDH）方法计算了吡嗪分子的S（2）（pi pi（*））吸收谱，其扩散结构是由S（2）-S（1）锥交点处的超快非绝热动力学引起的.采用Raab [J. Chem. Phys. 110，936（1999）]的24模二阶振动耦合模型，沿着该模型的4模和10模降维变体。G-MCTDH可以用作全高斯方法，也可以用作混合方法，其使用划分成由常规MCTDH基函数处理的主模式和由高斯粒子描述的次模式。与标准MCTDH计算结果的比较表明，该方法收敛于精确结果。移动高斯基的变分非经典演化是获得收敛的关键因素。对于高维系统，收敛速度显着加快，如果该方法是采用混合格式。
The Gaussian-based multiconfiguration time-dependent Hartree (G-MCTDH) method is applied to calculate the S(2)(pi pi(*)) absorption spectrum of the pyrazine molecule, whose diffuse structure results from the ultrafast nonadiabatic dynamics at the S(2)-S(1) conical intersection. The 24-mode second-order vibronic-coupling model of Raab [J. Chem. Phys. 110, 936 (1999)] is employed, along with 4-mode and 10-mode reduced-dimensional variants of this model. G-MCTDH can be used either as an all-Gaussian approach or else as a hybrid method using a partitioning into primary modes, treated by conventional MCTDH basis functions, and secondary modes described by Gaussian particles. Comparison with standard MCTDH calculations shows that the method converges to the exact result. The variational, nonclassical evolution of the moving Gaussian basis is a key element in obtaining convergence. For high-dimensional systems, convergence is significantly accelerated if the method is employed as a hybrid scheme.