Ultrafast Photodissociation Dynamics of Ni(CO)4
Ultrafast Photodissociation Dynamics of Ni(CO)4
复制标题
Ni(CO)4 的超快光解离动力学
DOI：
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发表时间：
2001
期刊：
影响因子：
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通讯作者：
S. Trushin
中科院分区：
文献类型：
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作者：
W. Fuß;A. Schmid;S. Trushin
通过时间分辨非共振（800 nm）多光子电离，我们发现六个连续的指数过程后，在气相中的Ni（CO）4在267 nm处激发。多达四个步骤（时间常数22至70 fs）可能对应于完整分子中金属到配体电荷转移状态之间的弛豫和内部转换。只有下一个步骤（600 fs）代表CO基团的消除。这比迄今为止研究的大多数其他羰基金属慢一个数量级。解离产物是处于S1状态的Ni（CO）3。它不会弛豫到基态，而是发光（可能是在系统间穿越之后）。这意味着缺乏一个容易接近的S1/S 0圆锥相交。这种交叉是由Jahn-Teller效应在其他羰基化合物（因此不发光）中引起的，但在Ni（CO）3中没有。为了解释依赖于泵浦波长的时间常数（在260、267和276 nm处分别为42、55和113 ps），我们假设部分Ni（CO）3解离成电子。
By time-resolved nonresonant (800 nm) multiphoton ionization we found six consecutive exponential processes after excitation of Ni(CO)4 at 267 nm in the gas phase. Up to four steps (time constants 22 to 70 fs) probably correspond to relaxation and internal conversion between metal-to-ligand charge-transfer states in the intact molecule. Only the next step (600 fs) represents elimination of a CO group. This is an order of magnitude slower than in most other metal carbonyls investigated so far. The dissociation product is Ni(CO)3 in its S1 state. It does not relax to the ground state but luminesces (probably after intersystem crossing). This implies the absence of an easily accessible S1/S0 conical intersection. Such an intersection is induced by the Jahn−Teller effect in other carbonyls (which therefore do not luminesce), but not in Ni(CO)3. To explain a pump−wavelength-dependent time constant (42, 55, and 113 ps at 260, 267, and 276 nm, respectively), we assume that part of Ni(CO)3 dissociates to electron...