Electronic excitation functions by low-energy electron-impact spectroscopy. Restrictions to the trapped-electron methods

Near-Threshold Electron-Impact Excitation of the Low-Lying Rydberg States of Ethylene

“…The electronic spectrum of the ethylene molecule has been the subject of numerous experimental − and theoretical − studies. Electron energy loss spectroscopy, since it permits characterization of dipole- and spin-forbidden transitions, has played a particularly important role in elucidating the excited states of ethylene. − In this context, it should be noted that there are two distinct mechanisms for the production of electronically excited states via electron impact: (1) direct excitation and (2) indirect excitation proceeding through the formation and decay of intermediate temporary anion states …”

“…The electronic spectrum of the ethylene molecule has been the subject of numerous experimental [1][2][3][4][5][6][7][8][9] and theoretical [10][11][12][13][14][15][16][17][18] studies. Electron energy loss spectroscopy, since it permits characterization of dipole-and spin-forbidden transitions, has played a particularly important role in elucidating the excited states of ethylene.…”

“…Electron energy loss spectroscopy, since it permits characterization of dipole-and spin-forbidden transitions, has played a particularly important role in elucidating the excited states of ethylene. [2][3][4][5][6] In this context, it should be noted that there are two distinct mechanisms for the production of electronically excited states via electron impact: (1) direct excitation and (2) indirect excitation proceeding through the formation and decay of intermediate temporary anion states. 19 Most electron-energy-loss studies of the electronically excited states of ethylene have focused on direct excitation processes.…”