Excitation of the Gas-Phase Guanine Molecules by Electron Impact

The emission spectra of isolated guanine molecules have been obtained in the 250–500 nm wavelength range due to excitation by a beam of slow electrons. At a beam energy of 100 eV, nineteen spectral bands and lines have been observed in the spectrum. It has been shown that the guanine emission spectra are caused by processes of dissociative excitation of molecules, dissociative excitation with ionization, and by the primary excitation of the electronic levels of guanine. The biophysical implications of the obtained results are discussed.