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对乙酰基的基态（X12A′）和激发态进行了理论和实验研究。通过采用MRSDCI和MP2方法计算，获得了CH3CO自由基的四个电子激发态（A12A″，B22A′，C32A′，D22A″），其垂直激发能分别为250．8kJ·mol－1，472．3kJ·mol－1，645．8kJ·mol－1和674．7kJ·mol－1。运用时间分辨付里叶红外光谱仪（TR－FTIR）分别研究了CH3CO自由基的热解和光解反应，观察到初生产物CO（V）的红外发射光谱．势垒仅为75．2kJ·mol－1的基态CH3CO极易热解．532um的激光只能将CH3CO激发到束缚态A12A″，故未观察到CO信号；而248nm或266nm的激光可使CH3CO发生B22A′←X12A′跃迁，生成高振动激发的CO（V8）产物．
The theoretical and experimental studies on the ground state (X12A ’) and excited states of acetyl groups were carried out. By using the methods of MRSDCI and MP2, the four excited states (A12A “, B22A ’, C32A’, D22A”) of CH3CO radical were obtained and their vertical excitation energies were 250.8kJ · mol-1,472.3kJ · Mol -1,645.8 kJ · mol -1 and 674.7 kJ · mol -1. The pyrolysis and photolysis reactions of CH3CO radicals were studied by time-resolved Fourier transform infrared spectroscopy (TR-FTIR). The infrared emission spectra of CO (V) were observed. The ground state CH 3 CO with a potential barrier of only 75.2 kJ · mol -1 is extremely pyrolytic. The 532nm laser can only excite CH3CO to the bound state A12A ", so no CO signal is observed; while the 248nm or 266nm laser can make CH3CO undergo B22A ’← X12A’ transition to produce high vibration excited CO (V8) product.