Spectroscopic observation of (N{sub 2}){sub 2} dimers in free icosahedral N{sub 2} and Ar-N{sub 2} clusters

• Published in: Physical review. A, Atomic, molecular, and optical physics Atomic, molecular, and optical physics, 2011-08, Vol.84 (2)
• Main Authors: Doronin, Yu. S., Libin, M. Yu, Samovarov, V. N., Vakula, V. L.
• Format: Article
• Language: English
• Subjects: ARGON; ATOMIC AND MOLECULAR PHYSICS; DIMERS; LUMINESCENCE; MOLECULAR BEAMS; MOLECULES; NITROGEN; SPECTROSCOPY; VAN DER WAALS FORCES
• ISSN: 1050-2947; 1094-1622
• DOI: 10.1103/PHYSREVA.84.023201

Supersonic-jet luminescence spectroscopy was applied to study vibronic transitions in icosahedral N{sub 2} and Ar-N{sub 2} clusters having from 100 to 400 particles per cluster. In the case of mixed Ar-N{sub 2} clusters, the w {sup 1}{Delta}{sub u}{yields} X {sup 1}{Sigma}{sub g}{sup +} transitions were observed to occur in single N{sub 2} molecules in an Ar environment, in very much the same way as in Ar-N{sub 2} bulk samples. In N{sub 2} clusters, however, a band series was detected which, to our knowledge, was never observed earlier. In the spectra of Ar-N{sub 2} clusters, this series coexisted with the ''bulk''w {sup 1}{Delta}{sub u}{yields} X{sup 1}{Sigma}{sub g}{sup +} transitions. Our analysis demonstrated that the series should be assigned to emission of van der Waals (N{sub 2}){sub 2} dimers from inside clusters. Earlier, such dimers were only observed in molecular beams and gaseous nitrogen; this paper reports their observation in the solid phase of nitrogen. Our results can be of interest from the viewpoint of producing polymeric nitrogen since (N{sub 2}){sub 2} dimers can be considered to be a starting species for its synthesis.