Eur. Phys. J. D (2016) 70: 175
https://doi.org/10.1140/epjd/e2016-70308-1

Regular Article

Interactions of protons with furan molecules studied by collision-induced emission spectroscopy at the incident energy range of 50–1000 eV^*

¹ Department of Physics of Electronic Phenomena, Gdansk University of Technology, ul. G. Narutowicza 11/12, 80-233 Gdansk, Poland
² Institute of Experimental Physics, University of Gdansk, ul. Wita Stwosza 59, 80-952 Gdansk, Poland

^a e-mail: twasowicz@mif.pg.gda.pl
^b Present address: Gdynia Maritime University, ul. Morska 81-87, 81-225 Gdynia, Poland

Received: 6 May 2016
Received in final form: 5 July 2016
Published online: 30 August 2016

Abstract

Investigations of the ion-molecule reactions provide insight into many fields ranging from the stellar wind interaction with interstellar media, up to medicine and industrial applications. Besides the applications, the understanding of these processes is itself a problem of fundamental importance. Thus, interactions of protons with the gas-phase furan molecules have been investigated for the first time in the energy range of 50–1000 eV exploiting collision-induced emission spectroscopy. Recorded spectra reveal emission of the atomic H_β to H_θ lines of the hydrogen Balmer series and the molecular bands of vibrationally and rotationally excited diatomic CH fragments created in the A²Δ and B²Σ^- electronic states. The measurements of the emission yields of the excited fragments by recording their intensities at different projectile energies have been performed. The highest yields have been observed for production of hydrogen atoms which intensities rapidly decreased with increasing principal quantum number n. From the H (n = 4–7) intensity ratios depopulation factors of hydrogen excited states have been determined at each impact energy and possible collisional mechanisms leading to enhanced production of the hydrogen atoms have been suggested. We compare and discuss our results with improved data set of proton collisions with tetrahydrofuran (THF) molecules, the hydrogenated derivatives of furan.