Neumaier Marco, Hampe Oliver, Kappes Manfred M
Institut für Nanotechnologie, Forschungszentrum Karlsruhe, P.O. Box 3640, D-76021 Karlsruhe, Germany.
J Chem Phys. 2005 Aug 15;123(7):074318. doi: 10.1063/1.2008259.
Electron transfer collisions of trapped doubly charged fullerene anions C76(2-), C(78)2-, and C84(2-) with SF6 are studied in a Fourier transform ion cyclotron resonance mass spectrometer at center-of-mass collisional energies ranging from thermal energy to 77 eV. Collision energy dependencies manifest threshold energies for (nominally exoergic) single electron transfer onto SF6 of 1.46+/-0.3 eV, 1.56+/-0.3 eV, and 1.63+/-0.3 eV for C(76)2-, C78(2-), and C(84)2-, respectively. Kinetics studies reveal charge-transfer cross sections of up to 430+/-200 A2 for C84(2-) at a collision energy of 77 eV. The mechanism and the energetics are discussed in terms of classical electrostatic model calculations. Additionally, we rationalize the collision energy dependencies of the charge-transfer cross sections using the two-state Landau-Zener formalism to describe the associated resonant electron tunneling probability.
在傅里叶变换离子回旋共振质谱仪中，研究了捕获的双电荷富勒烯阴离子C76(2-)、C78(2-)和C84(2-)与SF6的电子转移碰撞，质心碰撞能量范围从热能到77 eV。碰撞能量依赖性表明，对于C76(2-)、C78(2-)和C84(2-)，（名义上为放能的）单电子转移到SF6上的阈值能量分别为1.46±0.3 eV、1.56±0.3 eV和1.63±0.3 eV。动力学研究表明，在77 eV的碰撞能量下，C84(2-)的电荷转移截面高达430±200 Å2。根据经典静电模型计算讨论了其机理和能量学。此外，我们使用双态朗道-齐纳形式来描述相关的共振电子隧穿概率，从而合理化了电荷转移截面的碰撞能量依赖性。
