1. Atomic Molecular and Optical Physics Research Group, Advanced Institute of Materials Science, Ton Duc Thang University, Ho Chi Minh City, Vietnam
2. Faculty of Applied Sciences, Ton Duc Thang University, Ho Chi Minh City, Vietnam
3. Department of Physics, Ho Chi Minh City University of Education, Ho Chi Minh City, Vietnam
4. Department of Chemistry, Graduate School of Science, Tohoku University, Sendai 980-8578 Japan