scholarly journals Time-Dependent Long-Range-Corrected Density-Functional Tight-Binding Method Combined with the Polarizable Continuum Model

2019 ◽  
Vol 123 (26) ◽  
pp. 5649-5659 ◽  
Author(s):  
Yoshio Nishimoto
Keyword(s):  
Long Range ◽  
Continuum Model ◽  
Density Functional ◽  
Tight Binding ◽  
Polarizable Continuum Model ◽  
Time Dependent ◽  
Tight Binding Method ◽  
Polarizable Continuum

scholarly journals Time-Dependent Long-Range Corrected Density-Functional Tight-Binding Method Combined with the Polarizable Continuum Model

2019 ◽  
Author(s):  
Yoshio Nishimoto
Keyword(s):  
Excited State ◽  
Long Range ◽  
Continuum Model ◽  
Density Functional ◽  
Tight Binding ◽  
Polarizable Continuum Model ◽  
Time Dependent ◽  
Dual Emission ◽  
Tight Binding Method ◽  
Polarizable Continuum

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>

scholarly journals Time-Dependent Long-Range Corrected Density-Functional Tight-Binding Method Combined with the Polarizable Continuum Model

2019 ◽  
Author(s):  
Yoshio Nishimoto
Keyword(s):  
Excited State ◽  
Long Range ◽  
Continuum Model ◽  
Density Functional ◽  
Tight Binding ◽  
Polarizable Continuum Model ◽  
Time Dependent ◽  
Dual Emission ◽  
Tight Binding Method ◽  
Polarizable Continuum

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>

The fragment molecular orbital method combined with density-functional tight-binding and the polarizable continuum model

2016 ◽  
Vol 18 (32) ◽  
pp. 22047-22061 ◽  
Author(s):  
Yoshio Nishimoto ◽  
Dmitri G. Fedorov
Keyword(s):  
Molecular Structure ◽  
Molecular Orbital ◽  
Continuum Model ◽  
Density Functional ◽  
Tight Binding ◽  
Polarizable Continuum Model ◽  
Orbital Method ◽  
Molecular Orbital Method ◽  
Polarizable Continuum ◽  
Structure Of Proteins

The electronic gap in proteins is analyzed in detail, and it is shown that FMO-DFTB/PCM is efficient and accurate in describing the molecular structure of proteins in solution.

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