High-resolution spectral analysis of hybrid A/B-type band of 1,3-butadiene at 6.2 mu m using an EC-QCL coupled with cavity ring-down spectroscopy

摘要

The fine rotational-vibrational spectra of long-chain molecules like 1,3-butadiene are very closely spaced and highly overlapped. Such investigations require high-sensitive techniques to avoid overlapping and adequate resolution to observe their fine structure spectra. In this work, we have utilized a high-resolution external cavity-quantum cascade laser at similar to 6.2 mu m coupled with high-sensitive cavity ring-down spectroscopy (CRDS) to determine the fine ro-vibrational spectra of 1,3-butadiene in the gas phase. We experimentally probed the hybrid A/B-type band at 1596.412 cm(-1) and also calculated relevant spectroscopic parameters of 1,3-butadiene using Gaussian 16 and subsequently simulated the spectra using PGOPHER simulation. Finally, we selected a unique interference-free spectral region within the 1,3-butadiene spectrum, and performed detailed ro-vibrational study of 3 spectral lines in this region. These results are a great advance over the earlier works and provide a spectroscopic window that may enable selective and high-sensitive sensing of 1,3-butadiene in the future.