F Melchert

Measurements of charge transfer in H+-He+ collisions

A crossed-beams experiment has been set up to study charge changing collisions between ions. Absolute cross sections for the charge transfer reaction H++He+ to H0+He2+ have been measured in the centre-of-mass energy range 8-100 keV using a coincidence technique for the detection of the reaction products. The data are compared with previous experimental and theoretical results.

Charge transfer in He+-He+ collisions

Cross sections for charge transfer in He+-He+ collisions have been measured in the centre-of-mass energy range 7-112 keV, using crossed beams and coincident detection of the reaction products. The results obtained are in excellent agreement with previous measurements by Peart et al in the CM energy range 19-57 keV. A two-state coupling calculation with asymptotically correct pseudomolecular states shows that the capture into the ground state of He is approximately only 50% of the total capture cross section at energies below the cross section maximum.

Electron detachment in collisions

Using the crossed-beams technique, we have measured absolute cross sections for the total production of in collisions between and ions by means of a beam-pulsing method for the detection for centre-of-mass energies between 1.4 and 39.8 keV. From the measured data cross sections for the electron detachment process were calculated using the total cross sections for mutual neutralization measured previously. The electron detachment results are in very good agreement with recent theoretical calculations.

Mutual neutralisation in H+-H- collisions

Cross sections for mutual neutralisation in H+-H- collisions have been measured in the CM energy range 1-40 keV, using crossed beams and coincident detection of the reaction products. The results extend smoothly the latest measurements by Peart et al. (1985) and Szucs et al. (1984) towards higher energies and they are partly in excellent accord with recent theoretical predictions.

Transfer ionization in H++H

Absolute cross sections for transfer ionization in H/sup +/+H/sup -/ collisions have been measured in the center-of-mass energy range 50 eV--40 keV, with the use of merged- and crossed-beam techniques, together with coincident detection of the products. A mechanism is proposed for the process in the low-energy region. The cross section, calculated accordingly, is found to be in satisfactory agreement with the experimental data.

Transfer ionization inH++H−collisions

Absolute cross sections for transfer ionization in H/sup +/+H/sup -/ collisions have been measured in the center-of-mass energy range 50 eV--40 keV, with the use of merged- and crossed-beam techniques, together with coincident detection of the products. A mechanism is proposed for the process in the low-energy region. The cross section, calculated accordingly, is found to be in satisfactory agreement with the experimental data.

Transfer ionization in H/sup +/+H/sup -/ collisions

Absolute cross sections for transfer ionization in H/sup +/+H/sup -/ collisions have been measured in the center-of-mass energy range 50 eV--40 keV, with the use of merged- and crossed-beam techniques, together with coincident detection of the products. A mechanism is proposed for the process in the low-energy region. The cross section, calculated accordingly, is found to be in satisfactory agreement with the experimental data.