Liu Chen-Lin, Hsu Hsu Chen, Hsu Yuan Chin, Ni Chi-Kung
Institute of Atomic and Molecular Sciences, Academia Sinica, P.O. Box 23-166, Taipei 10617, Taiwan.
J Chem Phys. 2007 Sep 14;127(10):104311. doi: 10.1063/1.2764077.
Energy transfer between highly vibrationally excited naphthalene and Kr atom in a series of translational collision energies (108-847 cm(-1)) was studied separately using a crossed-beam apparatus along with time-sliced velocity map ion imaging techniques. Highly vibrationally excited naphthalene in the triplet state (vibrational energy: 16,194 cm(-1); electronic energy: 21,400 cm(-1)) was formed via the rapid intersystem crossing of naphthalene initially excited to the S(2) state by 266 nm photons. The collisional energy transfer probability density functions were measured directly from the scattering results of highly vibrationally excited naphthalene. At low collision energies a short-lived naphthalene-Kr complex was observed, resulting in small amounts of translational to vibrational-rotational (T-->VR) energy transfer. The complex formation probability decreases as the collision energy increases. T-->VR energy transfer was found to be quite efficient at all collision energies. In some instances, nearly all of the translational energy is transferred to vibrational-rotational energy. On the other hand, only a small fraction of vibrational energy is converted to translational energy. The translational energy gained from vibrational energy extend to large energy transfer (up to 3000 cm(-1)) as the collision energy increases to 847 cm(-1). Substantial amounts of large V-->T energy transfer were observed in the forward and backward directions at large collision energies.
利用交叉束装置和时间切片速度映射离子成像技术，分别研究了在一系列平动碰撞能量（108 - 847 cm⁻¹）下，高振动激发萘与氪原子之间的能量转移。通过266 nm光子将萘初始激发到S(2)态后，经快速系间窜越形成处于三重态的高振动激发萘（振动能量：16,194 cm⁻¹；电子能量：21,400 cm⁻¹）。碰撞能量转移概率密度函数直接从高振动激发萘的散射结果中测量得到。在低碰撞能量下，观察到一个寿命较短的萘 - 氪复合物，导致平动向振动 - 转动（T→VR）的能量转移量较小。复合物形成概率随碰撞能量增加而降低。发现T→VR能量转移在所有碰撞能量下都相当高效。在某些情况下，几乎所有的平动能量都转移到了振动 - 转动能量上。另一方面，只有一小部分振动能量转化为平动能量。随着碰撞能量增加到847 cm⁻¹，从振动能量获得的平动能量扩展到较大的能量转移（高达3000 cm⁻¹）。在大碰撞能量下，在向前和向后方向都观察到了大量的大V→T能量转移。
