Li Ziman, Korobkova Ekaterina, Werner Kathryn, Shum Lawrence, Mullin Amy S
Department of Chemistry, Boston University, Boston, Massachusetts 02215, USA.
J Chem Phys. 2005 Nov 1;123(17):174306. doi: 10.1063/1.2098647.
Supercollision relaxation of highly vibrationally excited pyrazine (E(vib) = 37,900 cm(-1)) with D35Cl is investigated using high-resolution transient IR diode laser absorption spectroscopy at 4.4 microm. Highly excited pyrazine is prepared by pulsed UV excitation at 266 nm, followed by rapid radiationless decay to the ground electronic state. The rotational energy distribution of the scattered DCl (v = 0,J) molecules with J = 15-21 is characterized by T(rot) = 755+/-90 K. The relative translational energy increases as a function of rotational quantum number for DCl with T(rel) = 710+/-190 K for J = 15 and T(rel) = 1270+/-240 K for J = 21. The average change in recoil velocity correlates with the change in rotational angular momentum quantum number and highlights the role of angular momentum in energy gain partitioning. The integrated energy-transfer rate for appearance of DCl (v = 0,J = 15-21) is k(2)(int) = 7.1x10(-11) cm3 molecule(-1) s(-1), approximately one-eighth the Lennard-Jones collision rate. The results are compared to earlier energy gain measurements of CO2 and H2O.
利用4.4微米的高分辨率瞬态红外二极管激光吸收光谱，研究了高振动态激发的吡嗪（E(vib) = 37,900 cm(-1)）与D35Cl的超碰撞弛豫。高激发态的吡嗪通过266纳米的脉冲紫外激发制备，随后快速无辐射衰变至基电子态。散射的DCl（v = 0，J）分子（J = 15 - 21）的转动能量分布特征为T(rot) = 755±90 K。对于DCl，相对平动能随转动态量子数增加，J = 15时T(rel) = 710±190 K，J = 21时T(rel) = 1270±240 K。反冲速度的平均变化与转动角动量量子数的变化相关，突出了角动量在能量增益分配中的作用。DCl（v = 0，J = 15 - 21）出现的积分能量转移速率为k(2)(int) = 7.1x10(-11) cm3 molecule(-1) s(-1)，约为Lennard-Jones碰撞速率的八分之一。将结果与早期对CO2和H2O的能量增益测量进行了比较。
