Darr Joshua P, Glennon John J, Loomis Richard A
Department of Chemistry, Washington University, CB 1134 Saint Louis, MO 63130, USA.
J Chem Phys. 2005 Apr 1;122(13):131101. doi: 10.1063/1.1885001.
Laser-induced fluorescence and action spectroscopy experiments were performed to identify the origin of the Ar...I(2) continuum signals observed in and above the I(2) B-X spectral region. We have verified that these signals arise from transitions of the linear Ar...I(2) (X,v"=0) complex. The data provides no evidence that the excited state complexes undergo a one-atom caging mechanism when prepared above the I(2)(B) dissociation limit, Ar...I(2) (B)-->Ar+I+I-->Ar+I(2)(B,v'). Instead, our results indicate that the continuum signals result from bound-free transitions of the linear Ar...I(2) X,v(")=0) complex to the inner repulsive walls of numerous Ar+I(2)(B,v') intermolecular potentials. The bound-free continuum signal associated with transitions to each Ar+I(2)(B,v') potential spans an energy region >700 cm(-1). We have found that the continuum signals turn-on 250(2)cm(-1) above the corresponding I(2) B-X,v'-0 band origin, and this energy represents the binding energy of the linear Ar...I(2) (X,v"=0) conformer, D(0) (")(L)=250(2)cm(-1).
进行了激光诱导荧光和作用光谱实验，以确定在I₂ B - X光谱区域内及以上观察到的Ar...I₂连续谱信号的起源。我们已经证实，这些信号来自线性Ar...I₂ (X, v" = 0)复合物的跃迁。数据没有提供证据表明，当在I₂(B)解离极限以上制备时，激发态复合物会经历单原子笼蔽机制，即Ar...I₂ (B)* --> Ar + I + I* --> Ar + I₂(B, v')。相反，我们的结果表明，连续谱信号是由线性Ar...I₂ (X, v" = 0)复合物到众多Ar + I₂(B, v')分子间势的内排斥壁的束缚-自由跃迁产生的。与跃迁到每个Ar + I₂(B, v')势相关的束缚-自由连续谱信号跨越一个>700 cm⁻¹的能量区域。我们发现，连续谱信号在相应的I₂ B - X, v' - 0带起源上方250(2)cm⁻¹处开启，并且这个能量代表线性Ar...I₂ (X, v" = 0)构象异构体的结合能，D₀(")(L) = 250(2)cm⁻¹。
