Laser Spectroscopy Facility, Department of Chemistry, The Ohio State University 120 W. 18th Avenue, Columbus Ohio 43210, USA.
Phys Chem Chem Phys. 2010 May 14;12(18):4773-82. doi: 10.1039/b924323b. Epub 2010 Mar 18.
We have obtained high resolution, partially rotationally resolved, jet-cooled cavity ringdown spectra of the origin band of the A<--X electronic transition of two of the five conformers (G(1)G(2) and G(1)T(2)) of the normal propyl peroxy radical, C(3)H(7)O(2), as well as the G conformer of the iso-propyl peroxy radical isomer. This transition, located in the near infrared, was studied using a narrow band laser source (less than or approximately 250 MHz) and a supersonic slit-jet expansion coupled with an electric discharge allowing us to obtain rotational temperatures of about 15 K. All three spectra have been successfully fitted using an evolutionary algorithm approach with a Hamiltonian including rotational and spin-rotational terms. Excellent agreement with the experimental spectra was obtained by fitting seven molecular parameters in each of the ground and the first excited electronic states as well as the band origin of the electronic transition. These parameters are compared with the results from electronic structure calculations. This analysis confirms unambiguously the previous room-temperature conformer assignments that were based upon quantum chemistry calculations.
我们获得了高分辨率、部分旋转分辨、射流冷却腔衰减光谱，这是正丙氧基自由基（C3H7O2）的两种构象（G1G2 和 G1T2）和异丙氧基自由基异构体的 G 构象的 A-X 电子跃迁的原始带。该跃迁位于近红外区域，使用窄带激光源（小于或约 250 MHz）和超声狭缝喷射扩展与放电相结合进行研究，使我们能够获得约 15 K 的旋转温度。使用包含旋转和自旋-旋转项的哈密顿量，通过进化算法方法成功拟合了所有三个光谱。通过拟合每个基态和第一激发电子态以及电子跃迁的带原始七个分子参数，与实验光谱得到了极好的一致性。这些参数与电子结构计算的结果进行了比较。这种分析明确证实了以前基于量子化学计算的室温构象分配。
