Predication of second-order optical nonlinearity of [(Bu2tIm)AuX] (X=halogen) using time-dependent density-functional theory combined with sum-over-states method

2005 ◽  
Vol 123 (13) ◽  
pp. 134302 ◽  
Author(s):  
Guochun Yang ◽  
Zhongmin Su ◽  
Chunsheng Qin ◽  
Yahui Zhao
2007 ◽  
Vol 06 (03) ◽  
pp. 585-594 ◽  
Author(s):  
YONGQING QIU ◽  
XIAOHONG WANG ◽  
YICHUN LIU ◽  
GUOCHUN YANG ◽  
HUI CHEN

Time-dependent density functional theory (TD-DFT) formalism is employed to calculate the electronic spectra of A 3 B 3 II–VI semiconductor clusters based on the geometrical structures optimized at DFT-B3LYP level. Moreover, their second-order nonlinear optical (NLO) properties are performed by TD-B3LYP combined with sum-over-states (SOS) formula. The calculation results indicate that it is necessary to consider the effective core potential and electron correlation effects when the basis sets are chosen for the heavy atoms. In addition, the results show that the transition energies and HOMO–LUMO gaps of the A 3 B 3 II–VI semiconductor clusters decrease, while the second-order nonlinear optical responses increase with the increasing of VI-group ionic radius. As a result, the SOS formula is valuable to calculate the βμ in the summation of 120 states. Meanwhile, charge transfers from the π bonding to π anti-bonding orbitals between II and VI group atoms significantly contribute to the second-order NLO properties.


2019 ◽  
Author(s):  
Kamal Batra ◽  
Stefan Zahn ◽  
Thomas Heine

<p>We thoroughly benchmark time-dependent density- functional theory for the predictive calculation of UV/Vis spectra of porphyrin derivatives. With the aim to provide an approach that is computationally feasible for large-scale applications such as biological systems or molecular framework materials, albeit performing with high accuracy for the Q-bands, we compare the results given by various computational protocols, including basis sets, density-functionals (including gradient corrected local functionals, hybrids, double hybrids and range-separated functionals), and various variants of time-dependent density-functional theory, including the simplified Tamm-Dancoff approximation. An excellent choice for these calculations is the range-separated functional CAM-B3LYP in combination with the simplified Tamm-Dancoff approximation and a basis set of double-ζ quality def2-SVP (mean absolute error [MAE] of ~0.05 eV). This is not surpassed by more expensive approaches, not even by double hybrid functionals, and solely systematic excitation energy scaling slightly improves the results (MAE ~0.04 eV). </p>


Author(s):  
Huimin Guo ◽  
Xiaolin Ma ◽  
Zhiwen Lei ◽  
Yang Qiu ◽  
Bernhard Dick ◽  
...  

The electronic structure and photophysical properties of a series of N-Methyl and N-Acetyl substituted alloxazine (AZs) were investigated with extensive density functional theory (DFT) and time-dependent density functional theory (TD-DFT)...


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