Peebles Sean A, Serafin Michal M, Peebles Rebecca A, Guirgis Gamil A, Stidham Howard D
Department of Chemistry, Eastern Illinois University, 600 Lincoln Avenue, Charleston, Illinois 61920, USA.
J Phys Chem A. 2009 Apr 2;113(13):3137-42. doi: 10.1021/jp811049n.
The rotational spectra belonging to the (28)Si isotopologue for three conformers of diethyldifluorosilane (Et(2)SiF(2)) and three conformers of diethylsilane (Et(2)SiH(2)) have been measured between 4 and 17 GHz by using pulsed-jet Fourier-transform microwave spectroscopy. Rotational spectra for the gauche-gauche, trans-trans, and trans-gauche conformers were identified for both molecules, while the significantly higher energy gauche-gauche' conformer was not observed. Ab initio calculations at the MP2(Full)/6-311+G(2d,2p) and MP2(Full)/6-311+G(2df,2pd) levels for the fluorine and the hydrogen analogues, respectively, provided rotational constants, dipole moment components, and the relative energies of the conformers to assist in the spectral assignment. In both molecules, the gauche-gauche conformer was identified by the ab initio calculations as the most stable. Agreement of the ab initio rotational constants with those from experiment was at worst 5%, with most rotational constants being predicted to within 2%.
通过脉冲喷射傅里叶变换微波光谱法，在4至17吉赫兹之间测量了二乙基二氟硅烷（Et(2)SiF(2)）的三种构象异构体和二乙硅烷（Et(2)SiH(2)）的三种构象异构体的(28)Si同位素分子的转动光谱。对于这两种分子，均识别出了gauche-gauche、trans-trans和trans-gauche构象异构体的转动光谱，而能量明显更高的gauche-gauche'构象异构体未被观测到。分别在MP2(Full)/6-311+G(2d,2p)和MP2(Full)/6-311+G(2df,2pd)水平上对氟代和氢代类似物进行的从头算计算，提供了转动常数、偶极矩分量以及构象异构体的相对能量，以辅助光谱归属。在这两种分子中，从头算计算均表明gauche-gauche构象异构体最稳定。从头算转动常数与实验值的一致性最差为5%，大多数转动常数的预测误差在2%以内。
