SCC-DFTB calculation of the static first hyperpolarizability: from gas phase molecules to functionalized surfaces.
SCC-DFTB calculation of the static first hyperpolarizability: from gas phase molecules to functionalized surfaces.
复制标题
静态第一超极化率的 SCC-DFTB 计算：从气相分子到功能化表面。
DOI：
10.1063/1.4806259
复制
发表时间：
2013
期刊：
影响因子：
--
通讯作者：
B. Champagne
中科院分区：
文献类型：
--
作者：
S. Nénon;B. Champagne
用自一致电荷密度泛函紧密结合（SCC-DFTB）方法计算π共轭化合物的第一超极化率，并与高阶从头算方法和密度泛函理论（DFT）计算结果进行了比较。SCC-DFTB方法的性能与PBE XC函数的DFT相似或更好。因此，如果对于小π共轭连接体SCC-DFTB可以再现趋势，那么对于较长的链，第一超极化率被高估了。在推挽式噻吩的情况下，β值被严重高估，B3LYP和PBE XC官能团也是如此。另一方面，SCC-DFTB方法密切再现了对二取代苯中β的进化，作为供体和受体基团的函数，估计在MP2水平上。SCC-DFTB测定键长交替和芳香环间二面角的可靠性也得到了解决，表明两者都被低估了。总的来说，SCC-DFTB计算与传统PBE XC函数计算的质量相同，但SCC-DFTB计算的计算要求非常低，因此可以用于非常大的系统，用于筛选非线性光学材料以及评估结构-性质关系。用接枝在SiO2表面上的吲哚啉-恶唑烷分子开关的第一超极化性的应用说明了这一点。这使得我们能够确定(i)表面对连接取代基的供体/受体特性的影响，（ii）分子取向的影响，(iii) π共轭开关和表面之间的间隔剂的作用，（iv）表面对β对比的整体影响，以及(v)分子开关在吸附时可以保持这种对比的事实。
The performance of the self-consistent charge density functional tight binding (SCC-DFTB) method for calculating the first hyperpolarizability of π-conjugated compounds has been assessed with respect to results obtained with high-level ab initio methods and density functional theory (DFT). The SCC-DFTB method performs similarly or better than DFT with the PBE XC functional. Thus, if for small π-conjugated linkers SCC-DFTB can reproduce trends, for longer chains the first hyperpolarizabilities are overestimated. In the case of push-pull thiophenes, the β values are strongly overestimated, as it is also the case with the B3LYP and PBE XC functionals. On the other hand, the SCC-DFTB method closely reproduces the evolution of β in p-disubstituted benzenes as a function of the donor and acceptor groups, as estimated at the MP2 level. The reliability of SCC-DFTB to determine the bond length alternation and the dihedral angles between the aromatic rings has also been tackled, demonstrating that both are underestimated. Overall, the SCC-DFTB calculations are of the same quality as those performed with the conventional PBE XC functional on which the method was parameterized but the SCC-DFTB calculations are computationally very little demanding, and it can therefore be adopted for very large systems for screening nonlinear optical materials as well as for assessing structure-property relationships. This is illustrated with an application on the first hyperpolarizability of an indolino-oxazolidine molecular switch grafted on a SiO2 surface. This has enabled to pinpoint (i) the effect of the surface on the donor/acceptor character of the linking substituent, (ii) the impact of molecular orientation, (iii) the role of a spacer between the π-conjugated switch and the surface, (iv) the global effect of the surface on the β contrast, and also (v) the fact that the molecular switches can maintain this contrast when adsorbed.
影响因子：
3.7
作者：
Elstner, M;Porezag, D;Seifert, G
通讯作者：
Seifert, G