1. Ordered Matter Science
Research Center, Southeast University, Nanjing 211189, Jiangsu, China
2. Consiglio Nazionale delle Ricerche (CNR-SPIN), Via Vetoio, I-67010 L’Aquila, Italy
3. International Centre
for Quantum and Molecular Structures and Physics Department, Shanghai University, 99 Shangda Road, Shanghai 200444 China
4. Institut
fuer Theoretische Physik und Astrophysik, Universitaet Wuerzburg, Am Hubland Campus Sued, Wuerzburg 97074, Germany
5. Institute of Physical Chemistry of Roumanian Academy, Splaiul Independentei 202, Bucharest 060021, Romania