Tran Ha, Li Gang, Ngo Ngoc Hoa, Ebert Volker
Laboratoire de Météorologie Dynamique, IPSL, CNRS, Sorbonne Université, Ecole polytechnique, Institut polytechnique de Paris, École normale supérieure, PSL Research University, F-75005 Paris, France.
Physikalisch-Technische Bundesanstalt, Bundesallee 100, 38116 Braunschweig, Germany.
Phys Chem Chem Phys. 2023 Apr 12;25(15):10343-10352. doi: 10.1039/d2cp04892b.
Super-Lorentzian effects in the troughs between lines and the pressure dependence of the line intensities retrieved from fits of absorption spectra of pure HCl have been investigated both experimentally and theoretically. For that, spectra of pure HCl gas in the 2-0 band were recorded with a Fourier Transform spectrometer at room temperature and for pressures ranging from 1 to 10 atm. The line intensities, retrieved from fits of the measurements with the Voigt profile using a single spectrum fitting technique, reveal large decreases with increasing pressure - up to 3% per atm - with a relatively weak rotational dependence. We also show that the absorptions in-between successive and transitions are significantly larger than those predicted using Voigt profiles. Requantized classical molecular dynamics simulations were made in order to predict absorption spectra of pure HCl matching the experimental conditions. The pressure dependence of the intensities retrieved from the calculated spectra as well as the predicted super-Lorentzian behavior between lines are in good agreement with the measurements. Our analysis shows that these effects are essentially due to incomplete collisions, which govern the dipole auto-correlation function at very short times.
研究了谱线间波谷中的超洛伦兹效应以及从纯HCl吸收光谱拟合中获取的谱线强度与压力的关系，包括实验和理论研究。为此，使用傅里叶变换光谱仪在室温下以及1至10个大气压的压力范围内记录了纯HCl气体在2 - 0带的光谱。通过使用单光谱拟合技术，用沃伊特轮廓对测量数据进行拟合得到的谱线强度显示，随着压力增加强度大幅下降——每大气压高达3%——且旋转依赖性相对较弱。我们还表明，连续 和 跃迁之间的吸收明显大于使用沃伊特轮廓预测的吸收。进行了重新量化的经典分子动力学模拟，以预测与实验条件匹配的纯HCl吸收光谱。从计算光谱中获取的强度与压力的关系以及谱线间预测的超洛伦兹行为与测量结果吻合良好。我们的分析表明，这些效应主要是由于不完全碰撞，这种碰撞在极短时间内控制着偶极自相关函数。
