Interference effects in the ionization of H₂by fast charged projectiles

Abstract

A theoretical investigation of the experimentally observed (Stolterfoht N et al 2001 Phys. Rev. Lett. 87 023201) interference effects in the double differential cross sections for ionization of the hydrogen molecule by fast ion impact is reported. The H2/2H cross section ratios as a function of the ejected electron velocity show an oscillating pattern, for which Stolterfoht et al propose a formula C + G sin(k D)/(k D), where k is the electron momentum and D the internuclear separation in H2. Our analysis in its simplest form leads instead to a formula C + G sin(k|| D)/(k|| D) where k|| is the component of k parallel to the projectile velocity. The presented theoretical model thus explains why at 90° the interference pattern will be strongly suppressed. In addition to the simplified analysis a numerical evaluation of a more accurate model is presented, confirming the latter qualitative prediction.

Periodic Variations in the Wavelength Distributions following Photon Interferences: Analogy with Electron Interferences

“…Since this hypothesis, the wave nature of the electron has been demonstrated in numerous experiments, by observing diffraction or interference patterns resulting in electron scattering on matter, for example, [2][3][4][5][6][7][8][9][10]. During the last years, electron interference effects have been widely investigated in electron-and ion-induced ionization [7][8][9][10][11][12][13][14][15][16][17][18], as well as in photoionization [19][20][21][22][23][24][25][26][27] of isolated atoms and molecules. In the electron interference experiments [5][6][7][8][9][10][11][12][13][14][15][19][20][21][22][23], each single electron hits the position-sensitive detector like a particle but traverses the interferometer slits (or scatters on atomic centers) like a wave.…”

Interference effects in the ionization of diatomic molecules

“…Concerning the ionization by charged projectiles, the theory for the first-order [6] and second-order [15] theory have been described in detail elsewhere. The cross section is obtained by integrating over the impact parameter and averaging over the angles of the molecular axis the transition probability, which is the sum of the first and second-order amplitudes…”

“…In the last few years special interest was given to the study of these effects. Interference has been evidenced experimentally [2][3][4][5] and has been investigated theoretically [6][7][8][9][10] by several groups for the charged particle impact ionization. In case of the photoionization there are mainly theoretical descriptions [11,12], but interference can be evidenced from the published experimental data [13], as it was shown in [14].…”

“…In our previous studies [6,14], in order to perform the calculations analytically, the final states have been described by plane waves, and the interference pattern was governed only by the two-center character of the initial wavefunction. The experimental study of Stolterfoht et al [4] suggested that the details of the interference effects may be influenced by the two-center character of the final state.…”

Impact ionization of molecular oxygen by 3.5-MeV/u bare carbon ions

“…It was predicted earlier [12][13][14] that a diatomic molecule can act as a molecular double slit in ionization by photons, electrons, or heavy ions, which is revealed as oscillations in the electron emission spectrum due to the interference effect. Now there has been rapid progress in this * Electronic address: lokesh@tifr.res.in field through ionization studies of H 2 molecules both experimentally [15][16][17][18][19][20][21][22] and theoretically [23,24]. Even the existence of a double-frequency component in the oscillatory structure has been debated [25][26][27] in the case of ionization of H 2 .…”