We investigated high-order harmonic generation in molecules N₂ and C₆H₆ irradiated by bichromatic counter-rotating circularly polarized laser pulses by using time-dependent density-functional theory methods. It is found that $3N$ ( $N$ is an integer) order harmonics in C₆H₆ disappear. Whereas, $N$ order harmonics are obtained in N₂. Analysis of the high harmonic generated from individual electronic orbital of the molecule, shows that, the characteristics of harmonic spectra are determined by the spatial distribution of electronic orbits. Moreover, effects of molecular orientation on harmonic emission are also presented.

中文翻译：

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双色反向旋转圆偏振激光脉冲照射分子产生高阶谐波的多电子效应

我们通过使用时间相关的密度泛函理论方法研究了双色反向旋转圆偏振激光脉冲照射的分子 N ₂和 C ₆ H _{6 中的}高次谐波生成。发现 $3N$ ( $N$ 是整数）C ₆ H _{6 中的}阶次谐波消失。然而， $N$ 在 N ₂中获得阶次谐波。对分子单个电子轨道产生的高次谐波的分析表明，谐波光谱的特性是由电子轨道的空间分布决定的。此外，还介绍了分子取向对谐波发射的影响。