Chatterley Adam S, Christiansen Lars, Schouder Constant A, Jørgensen Anders V, Shepperson Benjamin, Cherepanov Igor N, Bighin Giacomo, Zillich Robert E, Lemeshko Mikhail, Stapelfeldt Henrik
Department of Chemistry, Aarhus University, Langelandsgade 140, DK-8000 Aarhus C, Denmark.
Institute of Science and Technology Austria, Am Campus 1, 3400 Klosterneuburg, Austria.
Phys Rev Lett. 2020 Jul 3;125(1):013001. doi: 10.1103/PhysRevLett.125.013001.
Alignment of OCS, CS_{2}, and I_{2} molecules embedded in helium nanodroplets is measured as a function of time following rotational excitation by a nonresonant, comparatively weak ps laser pulse. The distinct peaks in the power spectra, obtained by Fourier analysis, are used to determine the rotational, B, and centrifugal distortion, D, constants. For OCS, B and D match the values known from IR spectroscopy. For CS_{2} and I_{2}, they are the first experimental results reported. The alignment dynamics calculated from the gas-phase rotational Schrödinger equation, using the experimental in-droplet B and D values, agree in detail with the measurement for all three molecules. The rotational spectroscopy technique for molecules in helium droplets introduced here should apply to a range of molecules and complexes.
测量了嵌入氦纳米液滴中的OCS、CS₂和I₂分子在由非共振、相对较弱的皮秒激光脉冲进行旋转激发后随时间的取向。通过傅里叶分析获得的功率谱中的明显峰值用于确定转动常数B和离心畸变常数D。对于OCS，B和D与红外光谱已知值相符。对于CS₂和I₂，它们是首次报道的实验结果。使用实验测得的液滴内B和D值，根据气相转动薛定谔方程计算出的取向动力学与这三种分子的测量结果在细节上相符。这里介绍的用于氦液滴中分子的转动光谱技术应适用于一系列分子和配合物。
