Rotational Isomers as Studied by Electronic Spectra

采用不同的电子能谱结合超音速射流技术研究了几种o-和m-取代苯酚的旋转异构体。发现由羟基取向产生的旋转异构体很容易通过它们的电子激发能来识别。用双色电离阈值光谱准确测定了各旋转异构体的电离势。所研究的分子的不同旋转异构体的电离势相差很大，可达200 cm^<-1>，这表明用电离方法分离旋转异构体是可能的。从超音速射流的电子光谱中还发现，旋转异构体选择性地与特定溶剂分子形成配合物。对旋转异构体的振幅运动和分子内氢键进行了详细的研究。

The rotational isomers of several o- and m-substituted phenolos have been studied by using various electronic spectroscopies combined with the supersonic jet technique. It was found that the rotational isomers arising from the orientation of the OH group are easily identified by their electronic excitation energies. The ionization potentials of the individual rotational isomers were accurately determined by two-color ionization threshold spectroscopy. The ionization potentials of the different rotational isomers of the molecule studied show a great difference as large as 200 cm^<-1>, which suggests the possibility of separation of the rotational isomer by the ionization method. It was also found from the electronic spectra in supersonic jets that the rotational isomer selectively forms the complexes with particular solvent molecules. The large amplitude motion and intramolecular hydrogen bonding in the rotational isomer were also studied in detail.