TAO-DFT-Based Molecular Dynamics.

Recently, AIMD ( 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 -acenes containing linearly fused benzene rings ( = 2-8) at 300 K. According to the TAO-AIMD simulations, on average, the smaller -acenes (up to = 5) possess a nonradical nature, and the larger -acenes ( = 6-8) possess an increasing radical nature, showing remarkable similarities to the ground-state counterparts at 0 K. Besides, the infrared spectra of -acenes obtained with the TAO-AIMD simulations are in qualitative agreement with the existing experimental data.