Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Drive, Pasadena, California 91109-8099, USA.
J Phys Chem A. 2010 Nov 18;114(45):12021-7. doi: 10.1021/jp105605f. Epub 2010 Oct 25.
Infrared (IR) absorption spectra of matrix-isolated HCCCH(2) have been measured. Propargyl radicals were generated in a supersonic pyrolysis nozzle, using a method similar to that described in a previous study (Jochnowitz, E. B.; Zhang, X.; Nimlos, M. R.; Varner, M. E.; Stanton, J. F.; Ellison, G. B. J. Phys. Chem. A 2005, 109, 3812-3821). Besides the nine vibrational modes observed in the previous study, this investigation detected the HCCCH(2) X̃ (2)B(1) out-of-plane bending mode (ν(8)) at 378.0 (±1.9) cm(-1) in a cryogenic argon matrix. This is the first experimental observation of ν(8) for the propargyl radical. In addition, seven overtone and combination bands have also been detected and assigned. Ab initio coupled-cluster anharmonic force field calculations were used to guide the analysis. Furthermore, ν(12), the HCCCH(2) in-plane bending mode, has been assigned to 333 (±10) cm(-1) based on the detection of its overtone (2ν(12), 667.7 ± 1.0 cm(-1)) and a possible combination band (ν(10) + ν(12), 1339.0 ± 0.8 cm(-1)). This is the first experimental estimation of ν(12) for the propargyl radical.
已测量了基质隔离 HCCCH(2) 的红外（IR）吸收光谱。使用类似于先前研究中描述的方法（Jochnowitz，E. B.；Zhang，X.；Nimlos，M. R.；Varner，M. E.；Stanton，J. F.；Ellison，G. B. J. Phys. Chem. A 2005，109，3812-3821），在超音速热解喷嘴中生成丙炔基自由基。除了先前研究中观察到的九个振动模式外，本研究还在低温氩气基质中检测到 HCCCH(2) X̃ (2)B(1)面外弯曲模式（ν(8)）为 378.0（±1.9）cm(-1)。这是丙炔基自由基ν(8)的首次实验观察。此外，还检测到并分配了七个泛频和组合带。使用从头算耦合簇非谐力场计算来指导分析。此外，根据其泛频（2ν(12)，667.7 ± 1.0 cm(-1))和可能的组合带（ν(10) + ν(12)，1339.0 ± 0.8 cm(-1))的检测，将 HCCCH(2)面内弯曲模式ν(12)分配至 333（±10）cm(-1)。这是丙炔基自由基ν(12)的首次实验估计。
