1. Department of Chemistry; University of Bristol; Cantocks Close Bristol. BS8 1TS UK
2. Department of Pure and Industrial Chemistry; Abia State University; Uturu PMB 2000. Abia State Nigeria
3. Centre of New Technologies; University of Warsaw; Banacha 2C 02089 Warszawa Poland
4. Institute for Spectroscopy; Russian Academy of Sciences; Fizicheskaya 5 142190, Moscow Troitsk Russia
5. Mestrelab Research S.L.; Feliciano Barrera 9B-Bajo 15706 Santiago de Compostela Spain