Competition between Alkalide Characteristics and Nonlinear Optical   Properties in OLi3-M-Li3O (M=Li, Na and K) Complexes
  Alkalides possess enhanced nonlinear optical (NLO) responses due to localization of excess electrons on alkali metals. We have proposed a new class of alkalides by sandwiching alkali atoms (M) between two Li3O superalkali clusters at MP2/6-311++G(d,p) level. We notice a competition between alkalide characteristics and NLO properties in OLi3-M-Li3O (M=Li, Na and K) isomers. For instance, the atomic charge on M (qM) in D2h structure is -0.58e for M=Li and its first static mean hyperpolarizablity (\b{eta}o) is 1 a.u., but in C2v structure, qM=-0.12e and \b{eta}o= 3.4*103 a.u. More interestingly, the \b{eta}o value for M=K (C2v) increases to 1.9*104 a.u. in which qM=0.24e. These findings may provide new insights into the design of alkalides, an unusual class of salts and consequently, lead to further researches in this direction. 
Ambrish Kumar Srivastava and Neeraj Misra
physics.atm-clus