DFTB/PCM Applied to Ground and Excited State Potential Energy Surfaces
DFTB/PCM Applied to Ground and Excited State Potential Energy Surfaces
复制标题
DFTB/PCM 应用于基态和激发态势能面
DOI：
10.1021/acs.jpca.5b10732
复制
发表时间：
2016
期刊：
影响因子：
--
通讯作者：
Yoshio Nishimoto
中科院分区：
文献类型：
--
作者：
加藤 奨;間平一輝;大村早紀;杉野未奈;林 康裕;K.Abe;Yoshio Nishimoto
考虑量子化学计算中的溶剂效应对于准确描述溶液中的势能面至关重要。在这项研究中，我们利用可极化连续介质模型（PCM）推导了时间依赖性密度泛函紧束缚（TD-DFTB）方法中基态和激发态能量的解析一阶几何导数的公式，TD-DFTB/PCM。然后通过一系列卤素交换 SN2 反应评估其性能。 DFTB/PCM 可以很好地再现分离的单卤代甲烷的 DFT 结果，但其过渡结构的一致性很大程度上取决于卤素元素。 TD-DFTB/PCM 的性能通过 3-羟基黄酮 (3HF) 在乙醇中的激发态分子内质子转移 (ESIPT) 反应进行评估。 TD-DFTB/PCM 在几何和能量方面相对较好地再现了 ESIPT 反应的势垒高度，但由于缺乏长程校正，它无法再现实验吸收和荧光能量。使用和不使用 PCM 的计算时序表明，C500H502 的 PCM 额外成本仅比真空中的相应计算高 10%。此外，通过将 TD-DFTB/PCM 应用于与染料复合的双链 DNA（PDB ID 108D），突出了 TD-DFTB/PCM 的潜在应用。我们得出的结论是，对于分别由超过 1000 个和 500 个原子组成的系统，TD-DFTB/PCM 单点计算和几何优化现在是可以管理的，并且必须谨慎解释使用 TD-DFTB 预测的属性。
Accounting for solvent effects in quantum chemical calculations is vital for the accurate description of potential energy surfaces in solution. In this study, we derive a formulation of the analytical first-order geometrical derivative of ground- and excited-state energies within the time-dependent density-functional tight-binding (TD-DFTB) method with the polarizable continuum model (PCM), TD-DFTB/PCM. The performance of this is then evaluated for a series of halogen-exchange SN2 reactions. DFTB/PCM reproduces DFT results well for isolated monohalogenated methanes, but its agreement for transition structures significantly depends on the halogen element. The performance of TD-DFTB/PCM is evaluated for the excited-state intramolecular proton transfer (ESIPT) reaction of 3-hydroxyflavone (3HF) in ethanol. TD-DFTB/PCM reproduces the barrier height of the ESIPT reaction in terms of geometry and energy relatively well, but it fails to reproduce the experimental absorption and fluorescence energies as a consequence of the absence of long-range corrections. Computational timings with and without PCM show that the additional cost of PCM for C500H502is only 10% greater than the corresponding calculation in vacuum. Furthermore, the potential applications of TD-DFTB/PCM are highlighted by applying it to a double-stranded DNA complexed with dye (PDB ID 108D). We conclude that TD-DFTB/PCM single-point calculations and geometry optimizations for systems consisting of more than 1000 and 500 atoms, respectively, is now manageable and that properties predicted with TD-DFTB must be interpreted with care.