The inelastic cross sections and rate coefficients for the rotational excitation of methanimine (CH₂NH) by cold H₂ have been determined quantum mechanically based on a new highly correlated five-dimensional potential energy surface. This surface was fitted to more than 60 000 ab initio points with a root-mean-square error of ∼1–2 cm^–1 in the region of the potential well whose depth is −374.0 cm^–1. The rotationally inelastic rate coefficients have been combined with spectroscopic data to generate the nonequilibrium spectrum of CH₂NH toward the interstellar molecular cloud Sgr B2(N). The transition 1₁₀ → 1₁₁ at 5.29 GHz is found to be inverted, and the predicted weak maser emission spectrum is in excellent agreement with new observations performed with the 100 m Green Bank Telescope.

中文翻译：

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星际甲胺亚胺的集体激发和弱Maser作用

基于新的高度相关的五维势能面，通过量子力学方法确定了冷H ₂对甲基苯胺（CH ₂ NH）的旋转激发的非弹性截面和速率系数。该表面被装配到超过60 000从头点与~1-2厘米的根均方误差^-1在势阱的深度是-374.0厘米的区域^-1。旋转非弹性速率系数已与光谱数据结合，以生成朝向星际分子云Sgr B2（N）的CH ₂ NH的非平衡光谱。过渡1 ₁₀ →1 ₁₁ 在5.29 GHz处发现其是倒转的，并且预测的弱maser发射光谱与100 m Green Bank望远镜进行的新观测非常吻合。