12CO(A1Π)与13CO(X1∑+)电子传能得多光子电离光谱研究

用双色共振多光子电离光谱(REMPI)方法, 在77 K温度下对~(12)CO(A~1H)与~(13)CO(X~1∑~+)之间的碰撞传能过程进行了研究. 发现二者之间的电子能量转移极快, 并测量了其不同振动通道的速率, 得到~(12)CO(A~1П)V=1、2、3与~(13)CO(X~1∑~+)V=0之间的电子传能总截面分别为1.14±0.42、0.22±0.04、0.17±0.06 nm, 还测量了产物的∧分裂П~+和П~-的布局比, 发现П~+布居总是多于П~-. 从激基复合物生成的观点对传能机理和∧双重态布居的倾向性进行了讨论。

The Electronic Energy Transfer Between 12CO(A1Π) and 13CO(X1∑+) Studied by Rempi Spectroscopy

The energy transfer processes between ~(12)CO(A~1Π) and ~(13)CO(X ~1Σ~+) were studied at 77 K by using the technique of two-color resonance enhanced multiphoton ionization spectroscopy. In a static cell with a mixture of 0.92 ~(13)CO + 0.08 ~(12)CO, ~(12)CO molecules were populated to the A state by 2-photon excitation using an UV dye laser. The ~(13)CO(A) resulted from the collision E-E energy transfer were detected by CO(A)→CO(B)→CO~+(X) 2-step ionization using a visible dye laser. The energy transfer processes were found to be very fast with total cross sections of 1.14±0.42, 0.22±0.04, 0.17±0.06 nm for ~(12)CO(A)V=1,2,3 respectively. We found that for different vibrational channels, cross section decreases with increasing energy mismatch ΔE. Another interesting result is that, for the ∧ doublet, the production of П~+ is always larger than that of П~-. The formation of an intermediate exciplex [OCCO]* is proposed to explain the experimental results.