Vibrational Feshbach resonances in electron attachment to carbon dioxide clusters
Vibrational Feshbach resonances in electron attachment to carbon dioxide clusters
复制标题
二氧化碳团簇电子附着的振动费什巴赫共振
DOI：
10.1007/s100530070049
复制
发表时间：
2000-10-01
影响因子：
1.8
通讯作者：
Hotop, H
中科院分区：
文献类型：
--
作者：
Leber, E;Barsotti, S;Hotop, H
用高分辨率(约为1 meV)激光光电子依附方法，研究了低能电子(1-180 meV)与(CO2)(N)(q小于等于N)团簇碰撞中(CO2)(Q)(-)离子(q=4-22)的形成。以前报道的“零能共振”是在更大的电子带宽上观察到的，实际上是由几个[(CO2)(N-1)CO2(nu(I))](-)类型的窄振动Feshbach共振组成的，它涉及一个振动激发的分子组分(nu(I)大于或等于1表示振动模)和一个被长程力弱束缚到团簇的扩散电子。共振发生在低于中性团簇[(CO_2)(N~(-1))CO_2(Nu(I))]的振动激发能的能量处；红移随着团簇离子尺寸Q的增加而增加约12 meV/单位；这些发现可以通过一个简单的依赖于尺寸的结合能的模型计算来恢复。团簇阴离子质量谱中的团簇阴离子尺寸分布主要反映了零能溶剂化位移振动共振的重叠量，团簇阴离子尺寸Q与附着的中性团簇的尺寸Q相同或接近。
Using a high resolution (Delta E approximate to 1 meV) laser photoelectron attachment method, we have studied the formation of (CO2)(q)(-) ions (q = 4-22) in collisions of low energy electrons (1-180 meV) with (CO2)(N) (q less than or equal to N) clusters. The previously reported "zero energy resonance", observed at much larger electron bandwidths, actually consists of several narrow vibrational Feshbach resonances of the type [(CO2)(N-1)CO2(nu(i))](-) which involve a vibrationally-excited molecular constituent (nu(i) greater than or equal to 1 denotes vibrational mode) and a diffuse electron weakly bound to the cluster by long range forces. The resonances occur at energies below those of the vibrational excitation energies of the neutral clusters [(CO2)(N-1)CO2(nu(i))]; the redshift rises with increasing cluster ion size q by about 12 meV per unit; these findings are recovered by a simple model calculation for the size dependent binding energies. The size distribution in the cluster anion mass spectrum, resulting from attachment of very slow electrons, mainly reflects the amount of overlap of solvation-shifted vibrational resonances with zero energy; the cluster anion size q is identical with or close to that of the attaching neutral cluster.