Shaozhi LiJENG-DA CHAI2021-07-282021-07-28202022962646https://www.scopus.com/inward/record.uri?eid=2-s2.0-85096227344&doi=10.3389%2ffchem.2020.589432&partnerID=40&md5=3709f120f6a566d6aa3d8abf79776cd9https://scholars.lib.ntu.edu.tw/handle/123456789/573480Recently, AIMD (ab initio 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 n-acenes containing n linearly fused benzene rings (n = 2–8) at 300 K. According to the TAO-AIMD simulations, on average, the smaller n-acenes (up to n = 5) possess a nonradical nature, and the larger n-acenes (n = 6–8) possess an increasing radical nature, showing remarkable similarities to the ground-state counterparts at 0 K. Besides, the infrared spectra of n-acenes obtained with the TAO-AIMD simulations are in qualitative agreement with the existing experimental data. ? Copyright ? 2020 Li and Chai.journal article10.3389/fchem.2020.5894322-s2.0-85096227344