Department of Chemistry, University of Utah, 315 S. 1400 E., Salt Lake City, Utah 84112, USA.
J Chem Phys. 2013 Sep 21;139(11):114305. doi: 10.1063/1.4820955.
The reaction of HOD(+) with N2O was studied over the collision energy (E(col)) range from 0.20 eV to 2.88 eV, for HOD(+) in its ground state and in each of its fundamental vibrational states: bend (010), OD stretch (100), and OH stretch (001). The dominant reaction at low E(col) is H(+) and D(+) transfer, but charge transfer becomes dominant for E(col) > 0.5 eV. Increasing E(col) enhances charge transfer only in the threshold region (E(col) < 1 eV), but all modes of HOD(+) vibrational excitation enhance this channel over the entire energy range, by up to a factor of three. For reaction of ground state HOD(+), the H(+) and D(+) transfer channels have similar cross sections, enhanced by increasing collision energy for E(col) < 0.3 eV, but suppressed by E(col) at higher energies. OD stretch excitation enhances D(+) transfer by over a factor of 2, but has little effect on H(+) transfer, except at low E(col) where a modest enhancement is observed. Excitation of the OH stretch enhances H(+) transfer by up to a factor of 2.5, but actually suppresses D(+) transfer over most of the E(col) range. Excitation of the bend mode results in ~60% enhancement of both H(+) and D(+) transfer at low E(col) but has little effect at higher energies. Recoil velocity distributions at high E(col) are strongly backscattered in the center-of-mass frame, indicating direct reaction dominated by large impact parameter collisions. At low E(col) the distributions are compatible with mediation by a short-lived collision complex. Ab initio calculations find several complexes that may be important in this context, and RRKM calculations predict lifetimes and decay branching that is consistent with observations. The recoil velocity distributions show that HOD(+) vibrational excitation enhances reactivity in all collisions at low E(col), while for high E(col) with enhancement comes entirely from the subset of collisions that generate strongly back-scattered product ions.
HOD(+)与 N2O 的反应在碰撞能量（E(col)）范围为 0.20 eV 至 2.88 eV 下进行研究，其中 HOD(+)处于基态和其基本振动状态：弯曲（010）、OD 拉伸（100）和 OH 拉伸（001）。在低 E(col)下，主要反应是 H(+)和 D(+)转移，但对于 E(col)>0.5 eV，电荷转移成为主要反应。增加 E(col)仅在阈值区域（E(col)<1 eV）增强电荷转移，但 HOD(+)振动激发的所有模式都在整个能量范围内增强了这个通道，最高可达三倍。对于基态 HOD(+)的反应，H(+)和 D(+)转移通道具有相似的截面，对于 E(col)<0.3 eV 的碰撞能量增加而增强，但在较高能量下受到抑制。OD 拉伸激发将 D(+)转移增强了一倍以上，但对 H(+)转移几乎没有影响，除了在低 E(col)下观察到适度增强。OH 拉伸激发将 H(+)转移增强了高达 2.5 倍，但在大部分 E(col)范围内实际上抑制了 D(+)转移。弯曲模式的激发在低 E(col)下导致 H(+)和 D(+)转移增强约 60%，但在较高能量下影响较小。高 E(col)下的反冲速度分布在质心框架中强烈后向散射，表明直接反应由大碰撞参数的碰撞主导。在低 E(col)下，分布与由短寿命碰撞复合物介导的情况相兼容。从头算计算发现了几种在这种情况下可能很重要的复合物，RRKM 计算预测了与观察结果一致的寿命和衰变分支。反冲速度分布表明，在低 E(col)下，HOD(+)振动激发增强了所有碰撞的反应性，而对于高 E(col)，增强完全来自于产生强烈后向散射产物离子的碰撞子集。
