Molecular dynamics simulations and anharmonic spectra of large PAHs

摘要

Due to the difficulties in obtaining high-resolution infrared (IR) spectra of polycyclic aromatic hydrocarbon molecules (PAHs) from experiments, current study of PAHs have led to an ever-increasing reliance on computational quantum chemistry. Our recent results show that the second-order vibrational perturbations theory (VPT2) produce accurate anharmonic spectra, which are consistent well with the high-resolution low-temperature gas-phase experimental spectra of PAHs (Chen 2018). However, such method suffers from low efficiency of calculation, it only works for small molecules (less than 24 C-atoms). Moreover, high symmetric (D6h) molecules (e.g. coronene and circumcoronene) can not be calculated with such method (Mackie et al. 2016), but these species are actually expected to be highly abundant in space given their remarkable stability (Bauschlicher et al.2008).