Simple preconditioning for time-dependent density functional perturbation theory

2011 ◽  
Vol 135 (1) ◽  
pp. 014103 ◽  
Author(s):  
Lauri Lehtovaara ◽  
Miguel A. L. Marques
Keyword(s):  
Perturbation Theory ◽  
Density Functional ◽  
Time Dependent ◽  
Density Functional Perturbation Theory ◽  
Dependent Density

A theoretical study of the structural and electronic properties of poly(9-vinylcarbazole) interacting with small-diameter single-walled carbon nanotubes

2020 ◽  
Vol 09 (02) ◽  
pp. 2050009
Author(s):  
V. W. Elloh ◽  
V. A. Apalangya ◽  
K. Kan-Dapaah ◽  
G. Gebreyesus ◽  
Abhishek K. Mishra ◽  
...  
Keyword(s):  
Perturbation Theory ◽  
Charge Transfer ◽  
Density Functional ◽  
Nonlinear Optical ◽  
Small Diameter ◽  
Time Dependent ◽  
Phonon Modes ◽  
Single Walled Carbon ◽  
Density Functional Perturbation Theory ◽  
Dependent Density

Density functional perturbation theory (DFPT) and time-dependent density functional perturbation theory (TDDFPT) calculations were employed to study the molecular and electronic structures, linear and nonlinear optical properties, optical phonon modes and vibrational properties of the interaction of poly(9-vinylcarbazole) (PVK)–small-diameter single-walled carbon nanotube (SWCNT) composites. Our calculations show that the chemical connection between PVK and SWCNTs is only through the relatively weak [Formula: see text]–[Formula: see text] and [Formula: see text]–H bonds. PVK and SWCNTs have different electron accepting abilities and we believe this is the major factor responsible for the charge transfer processes we observe in the calculations. We notice an increase in polarizability value from 152 a.u. (PVK) to 517 a.u. (PVK–SWCNTs), making the PVK–SWCNT composite an ideal model for applications such as mechanical and optoelectronics. Also, the result of our calculations under the time-dependent density functional perturbation theory hinges on the idea that the large value of the polarizability calculated for our composite model is an attribute which can be inferred to processes of charge transfer. Our finding corroborates the fact that non-covalent functionalization is one of the effective chemical methods by which the nonlinear optical response properties of PVK–SWCNT composite may be enhanced.

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