Development of Large-Scale Excited-State Calculations Based on the Divide-and-Conquer Time-Dependent Density Functional Tight-Binding Method

2019 ◽  
Vol 15 (3) ◽  
pp. 1719-1727 ◽  
Author(s):  
Nana Komoto ◽  
Takeshi Yoshikawa ◽  
Junichi Ono ◽  
Yoshifumi Nishimura ◽  
Hiromi Nakai
2007 ◽  
Vol 28 (16) ◽  
pp. 2589-2601 ◽  
Author(s):  
D. Heringer ◽  
T. A. Niehaus ◽  
M. Wanko ◽  
TH. Frauenheim

2019 ◽  
Author(s):  
Yoshio Nishimoto

In this study, excited-state free energies and geometries were efficiently evaluated using a linear-response time-dependent long-range corrected density-functional tight-binding method integrated with the polarizable continuum model (TD-LC-DFTB/PCM). Although the LC-DFTB method required the evaluation of the exchange-type term, which was moderately computationally expensive, a single evaluation of the excited-state gradient for a system consisting of more than 1000 atoms in a vacuum was completed within 30 minutes using one CPU core. Benchmark calculations were conducted for 3-hydroxy avone, which exhibits dual emission: the absorption and enol-form emission wavelengths calculated by TD-LC-DFTB/PCM agreed well with those predicted based on density functional theory using a long-range corrected functional; however, there was a large error in the predicted keto-form emission wavelength. Further benchmark calculations for more than 20 molecules indicated that the conventional TD-DFTB method underestimated the absorption and 0-0 transition energies compared with those which were measured experimentally while the TD-LC-DFTB method systematically overestimated these metrics. Nevertheless, the agreement of the results of the TD-LC-DFTB method with those obtained by the CAM-B3LYP method demonstrates the potential of the TD-LC-DFTB/PCM method. Moreover, changing the range-separation parameter to 0.15 minimized this deviation.<br>


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