State of the art in dissociative electron attachment spectroscopy and its prospects

Abstract

The latest achievements are presented in experimental and theoretical studies of resonance scattering of low-energy (0–15 eV) electrons from molecular targets in a gas phase resulting in the formation and decay of negative ions. The focus is on dissociative electron attachment spectroscopy for studying the microsecond dynamics of molecules containing an excess electron. Some studies of fundamental processes in isolated negative ions containing up to several electronvolts of excess energy are briefly described, and the possibility of using the results in interdisciplinary fields is discussed. A goal of the paper is to attract attention to the above-mentioned studies, which are rapidly developing abroad but only scarcely presented in the domestic literature.

Excitation of L-valine molecules by electrons and photons

“…As shown [23], the formation of negative ions during the interaction of electrons with biological molecules plays an important role in the energy range up to 10 eV.…”

“…The process of electron bombardment of a valine molecule in the region of low electron energies is as follows. In the energy range up to 7 eV, an electron is captured by the valine molecule and the fragmentation begins, as evidenced by the appearance of negative ions in the mass spectra [23]. In the range of electron energies above 8 eV, the thresholds for the appearance of positive ions of molecular fragments are observed [21].…”

“…Among such works on the determination of the mass spectra of molecules that make up amino acids should be mentioned: thymine [15], adenine [16][17][18], cytosine [18], uracil [19], guanine [20], valine [21], and glutamine and glutamic acid [22]. Another line of research is the study of elementary processes of excitation, dissociation and ionization of such molecules under the impact of electrons and photons [22][23][24][25][26].…”

“…It is determined by the fundamental characteristics of the target molecule and depends on the number of vibrational degrees of freedom, spatial structure, vibrational state, and electron affinity. A number of interesting works [22][23][24][25][26] are devoted to these processes; the most complete review of the current state and prospects of the spectroscopy of dissociative electron capture was performed in [22]. For biomolecules, for example, in [23], total dissociative electron capture cross-sections for thymine, cytosine, and adenine and for three compounds used as surrogates for the ribose were investigated.…”

“…A number of interesting works [22][23][24][25][26] are devoted to these processes; the most complete review of the current state and prospects of the spectroscopy of dissociative electron capture was performed in [22]. For biomolecules, for example, in [23], total dissociative electron capture cross-sections for thymine, cytosine, and adenine and for three compounds used as surrogates for the ribose were investigated. It was shown that cross-sections are roughly comparable magnitudes.…”