Infrared spectra of the CO₂–N₂ dimer are observed in the carbon dioxide ν₃ asymmetric stretch region (≈2350 cm⁻¹) using a tunable infrared optical parametric oscillator to probe a pulsed slit jet supersonic expansion. Previous results for the b-type fundamental band are extended to higher values of K_a. An a-type combination band involving the lowest in-plane intermolecular bending mode is observed. This yields a value of 21.4 cm⁻¹ and represents the first experimental determination of an intermolecular mode for CO₂–N₂. This intermolecular frequency is at odds with the value of 45.9 cm⁻¹ obtained from a recent 4D intermolecular potential energy surface. In addition, two weak bands near 2337 cm⁻¹ are assigned to the CO₂ hot band transition (v₁, v₂^l2, v₃) = (01¹1) ← (01¹0). They yield a value of 2.307 cm⁻¹ for the splitting of the degenerate CO₂ ν₂ bend into in-plane and out-of-plane components due to the presence of the nearby N₂. The in-plane mode lies at a lower energy relative to the out-of-plane mode.

中文翻译：

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在4.2μm区域内的CO2-N2二聚体的光谱：分子内CO2弯曲，分子间弯曲和基本K值较高的对称断裂。

的CO的红外光谱₂ -N ₂二聚体中的二氧化碳观察ν ₃不对称拉伸区域（≈2350厘米^-1使用可调的红外光参量振荡器来探测脉冲狭缝喷射的超声膨胀）。b型基带的先前结果扩展到了更高的K _a值。观察到涉及最低的面内分子间弯曲模式的a型结合带。得出的值为21.4 cm ^-1，代表了对CO ₂ -N ₂的分子间模式的首次实验测定。。该分子间频率与从最近的4D分子间势能面获得的45.9cm ^-1的值不一致。此外，将2337 cm ^-1附近的两个弱带分配给CO ₂热带转换（v ₁，v ₂ ^{l 2}，v ₃）=（01 ¹ 1）←（01 ¹ 0）。它们产生的2.307厘米的值^-1的简并CO的分束₂ ν ₂弯曲成在面内和面外部件由于的存在附近Ñ ₂。相对于平面外模式，平面内模式处于较低的能量。