Abstract:

By using ab initio and analytic energy gradients method, 43 optimized electronic states in 11 geometric configurations of AlCn and AlCn+ n=1~3 series are obtained at UHF (RHF)/3-21G level, their singles and doubles CI (CISD) energies are also obtained. 26 optimized electronic states in 7 geometric configurations of AlC4 and AlC4+ are obtained at UHF (RHF)/3-21G. In the point of energy, among those 69 configurations studied of AlCn and AlCn+ series, the most stable are of linear structures, and all the Al atoms are in the terminal. For AlC, AlC+, AlC2, AlC2+, AlC3, AlC3+, AlC4 and AlC4+, the most stable structures are AlCC, AlCC+, AlCCC, AlCCC+, AlCCCC and AlCCCC+ respectively. These results are consistent with theoretical and experimental results reported in references. In addition, harmonic vibrational analysises are performed on the most stable states of AlCn and AlCn+ n=1~4 series, namely AlC, AlCC, AlCCC, AlCCCC, AlC+, AlCC+, AlCCC+, AlCCCC+ by numerical method. Their fragmentation chanels, fragmentation energies and average binding energies are also investigated.

Key words: Ab initio, Atomic cluster, Stability, Fragmentation channels and energies