摘要
W<sub>HEN</sub> a dissociative system is subjected to an intense laser pulse, it will be photo-ionized. In the photo-ionization process, the dissociative system will develop a time-dependent dipole moment and emit an odd harmonic of the incident laser frequency. In the past ten years, optical harmomc generation has attracted much attention. This is because high optical harmonics will undoubtedly lead to the development of bright, short-pulse and versatile sources of coherent radiation in the vacuum ultraviolet （UV） and X-ray ranges. In addition, its ultrashort characteristic will be important for investigating many ultrafast phenomena. But people
