ELECTRONIC STRUCTURE AND STABILITY OF NH4(NH3)n AND NH4(NH3)m(H2O)n
ELECTRONIC STRUCTURE AND STABILITY OF NH4(NH3)n AND NH4(NH3)m(H2O)n
复制标题
NH4(NH3)n 和 NH4(NH3)m(H2O)n 的电子结构和稳定性
DOI：
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发表时间：
1996
期刊：
影响因子：
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通讯作者：
F. Misaizu
中科院分区：
文献类型：
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作者：
R. Takasu;K. Fuke;F. Misaizu
用飞行时间质谱研究了ArF准分子激光光解氨团簇和氨水混合团簇产生的NH 4（NH3）n和NH 4（NH3）m（H2O）n自由基的光电离过程。NH 4（NH3）n（n=0−35）和NH 4（NH3）m（H2O）n（m=0−4，n=0−3）的电离势（IPs）由光电离阈值测量确定。NH 4（NH3）n−1−NH3（n=1−6）的结合能由IPs估算。结果表明，NH_4和NH_3之间的成键是半离子型的。的IP为大的氨化NH 4团簇减少，增加n到35。发现极限值（n→∞）为1.33 eV，与液态NH3的光电发射阈值相一致。这一特征与最近发现的碱原子-氨团簇相似。NH_4（NH_3）_m（H_2O）_n的IP有明显的变化趋势，水分子越多，IP越高。这种趋势归因于与的结合能相比，的结合能较大。
The photoionization process of NH4(NH3)n and NH4(NH3)m(H2O)n radicals produced by an ArF excimer laser photolysis of ammonia clusters and ammonia–water mixed clusters are examined using time-of-flight mass spectroscopy. The ionization potentials (IPs) of NH4(NH3)n (n=0−35) and NH4(NH3)m(H2O)n (m=0−4, n=0−3) are determined by the photoionization threshold measurements. The binding energies of NH4(NH3)n−1−NH3 (n=1−6) are estimated from IPs. The results indicate that the bonding between NH4 and NH3 is semi-ionic. The IPs for the large ammoniated NH4 clusters decrease with increasing n up to 35. The limiting value (n→∞) is found to be 1.33 eV, which coincides with the photoemission threshold of liquid NH3. This feature is similar to those found recently for alkali-atom–ammonia clusters. A clear trend is found for the IPs of NH4(NH3)m(H2O)n; the clusters containing more water molecules have higher IP. This trend is ascribed to the large binding energy of comparing with that of .