We address ionization of a diatomic molecule by a bichromatic elliptically polarized field with co-rotating components. Using the strong-field approximation we investigate symmetry properties of the photoelectron momentum distribution and explore the minima which appear in the photoelectron spectra. We distinguish two types of minima: (i) two-center interference minima which appear due to the destructive interference of the contributions of two electron wave packets emitted from the two centers of the diatomic molecule and (ii) the one-center minima which are caused by the interference of the parts of the wave packet emitted from the same atomic center at different times. The position of the two-center interference minima depends on the molecular orientation. When a molecular orbital is modelled using the atomic orbitals of a specific parity, the position of the two-center interference minima does not depend on the ellipticity of our driving field. However, when a molecular orbital consists of both odd and even atomic orbitals the interference of their contributions and the position of the minima depend on the ellipticity. The position of the interference minima in the photoelectron momentum plane is confirmed using the saddle-point method. The position and the number of the one-center minima do not depend on the molecular orientation, but they strongly depend on the ellipticity of the field components. Finally, comparing the photoelectron spectra of the CO molecule with the spectra of homonuclear molecules and the NO molecule we show that the electron probability density distribution plays a significant role for the high-energy rescattered electrons.

中文翻译：

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共旋分量双色椭圆偏振场分子超阈值电离的特征

我们通过具有同向旋转分量的双色椭圆偏振场解决双原子分子的电离问题。使用强场近似，我们研究了光电子动量分布的对称特性，并探索了出现在光电子能谱中的最小值。我们区分两种类型的极小值：(i) 双中心干涉极小值，这是由于从双原子分子的两个中心发射的两个电子波包的贡献的相消干涉而出现的；(ii) 单中心极小值是由同一原子中心在不同时间发射的部分波包的干扰引起的。双中心干涉最小值的位置取决于分子方向。当使用特定宇称的原子轨道对分子轨道建模时，双中心干扰最小值的位置不取决于我们驱动场的椭圆率。然而，当一个分子轨道同时包含奇原子轨道和偶原子轨道时，它们贡献的干扰和最小值的位置取决于椭圆率。使用鞍点法确定光电子动量平面中干涉最小值的位置。单中心最小值的位置和数量不依赖于分子取向，但它们强烈依赖于场分量的椭圆率。最后，将 CO 分子的光电子能谱与同核分子和 NO 分子的光电子能谱进行比较，我们表明电子概率密度分布对高能再散射电子起着重要作用。