Gillies C. W., Gillies J. Z., Amadon S. J., Suenram R. D., Lovas F. J., Warner H., Malloy R.
Department of Chemistry, Rensselaer Polytechnic Institute, Troy, New York, 12180
J Mol Spectrosc. 2001 Jun;207(2):201-210. doi: 10.1006/jmsp.2001.8351.
Pulsed-beam Fourier transform microwave spectroscopy was used to observe and assign the rotational spectra of the argon-ketene van der Waals complex. Tunneling of the hydrogen or deuterium atoms splits the a- and b-type rotational transitions of H(2)CCO-Ar, H(2)(13)CCO-Ar, H(2)C(13)CO-Ar, and D(2)CCO-Ar into two states. This internal motion appears to be quenched for HDCCO-Ar where only one state is observed. The spectra of all isotopomers were satisfactorily fit to a Watson asymmetric top Hamiltonian which gave A=10 447.9248(10) MHz, B=1918.0138(16) MHz, C=1606.7642(15) MHz, Delta(J)=16.0856(70) kHz, Delta(JK)=274.779(64) kHz, Delta(K)=-152.24(23) kHz, delta(J)=2.5313(18) kHz, delta(K)=209.85(82) kHz, and h(K)=1.562(64) kHz for the A(1) state of H(2)CCO-Ar. Electric dipole moment measurements determined &mgr;(a)=0.417(10)x10(-30) C m [0.125(3) D] and &mgr;(b)=4.566(7)x10(-30) C m [1.369(2) D] along the a and b principal axes of the A(1) state of the normal isotopomer. A least squares fit of principal moments of inertia, I(a) and I(c), of H(2)CCO-Ar, H(2)(13)CCO-Ar, and H(2)C(13)CO-Ar for the A(1) states give the argon-ketene center of mass separation, R(cm)=3.5868(3) Å, and the angle between the line connecting argon with the center of mass of ketene and the C=C=O axis, θ(cm)=96.4 degrees (2). The spectral data are consistent with a planar geometry with the argon atom tilted toward the carbonyl carbon of ketene by 6.4 degrees from a T-shaped configuration. Copyright 2001 Academic Press.
脉冲束傅里叶变换微波光谱法用于观测和归属氩 - 乙烯酮范德华复合物的转动光谱。氢或氘原子的隧穿将H₂CCO - Ar、H₂¹³CCO - Ar、H₂C¹³CO - Ar和D₂CCO - Ar的a型和b型转动跃迁分裂为两个状态。对于HDCCO - Ar，这种内部运动似乎被淬灭了，只观测到一个状态。所有同位素异构体的光谱都能很好地拟合到一个沃森不对称陀螺哈密顿量，对于H₂CCO - Ar的A₁态，该哈密顿量给出A = 10447.9248(10) MHz，B = 1918.0138(16) MHz，C = 1606.7642(15) MHz，Δ(J) = 16.0856(70) kHz，Δ(JK) = 274.779(64) kHz，Δ(K) = - 152.24(23) kHz，δ(J) = 2.5313(18) kHz，δ(K) = 209.85(82) kHz，以及h(K) = 1.562(64) kHz。电偶极矩测量确定了沿正常同位素异构体A₁态的a和b主轴的μ(a) = 0.417(10)×10⁻³⁰ C m [0.125(3) D]和μ(b) = 4.566(7)×10⁻³⁰ C m [1.369(2) D]。对H₂CCO - Ar、H₂¹³CCO - Ar和H₂C¹³CO - Ar的A₁态的转动惯量主矩I(a)和I(c)进行最小二乘拟合，得到氩 - 乙烯酮质心间距R(cm) = 3.5868(3) Å，以及连接氩与乙烯酮质心的直线与C = C = O轴之间的夹角θ(cm) = 96.4度(2)。光谱数据与平面几何结构一致，氩原子从T形构型向乙烯酮的羰基碳倾斜6.4度。版权所有2001年学术出版社。
