AUTHOR=Li Shaozhi , Chai Jeng-Da 

TITLE=TAO-DFT-Based Ab Initio Molecular Dynamics

JOURNAL=Frontiers in Chemistry

VOLUME=8

YEAR=2020

URL=https://www.frontiersin.org/journals/chemistry/articles/10.3389/fchem.2020.589432

DOI=10.3389/fchem.2020.589432

ISSN=2296-2646

ABSTRACT=<p>Recently, AIMD (<italic>ab initio</italic> molecular dynamics) has been extensively employed to explore the dynamical information of electronic systems. However, it remains extremely challenging to reliably predict the properties of nanosystems with a radical nature using conventional electronic structure methods (e.g., Kohn-Sham density functional theory) due to the presence of static correlation. To address this challenge, we combine the recently formulated TAO-DFT (thermally-assisted-occupation density functional theory) with AIMD. The resulting TAO-AIMD method is employed to investigate the instantaneous/average radical nature and infrared spectra of <italic>n</italic>-acenes containing <italic>n</italic> linearly fused benzene rings (<italic>n</italic> = 2–8) at 300 K. According to the TAO-AIMD simulations, on average, the smaller <italic>n</italic>-acenes (up to <italic>n</italic> = 5) possess a nonradical nature, and the larger <italic>n</italic>-acenes (<italic>n</italic> = 6–8) possess an increasing radical nature, showing remarkable similarities to the ground-state counterparts at 0 K. Besides, the infrared spectra of <italic>n</italic>-acenes obtained with the TAO-AIMD simulations are in qualitative agreement with the existing experimental data.</p>