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Transfer processes in proton-helium collisions at high projectile energies

Yu.V. Popov
Skobeltsyn Nuclear Physics Institute, Lomonosov Moscow State University


Collaboration






Frankfurt experimental team headed by Doerner R. Culuunbaatar O., Joint Inst. for Nuclear Research, Dubna, Russia Houamer S., Univ. Ferhat Abbas, Setif, Algeria Galstyan A., Moscow State Univ., Moscow, Russia Popov Yu.V., Moscow State Univ., Moscow, Russia Dal Cappello C., Institut de Chimie, Physique et des MatИriaux Univ.
de Lorraine, Metz, France


Processes to consider


+ Charge transfer: p + He H + Heo + Transfer excitation: p + He H + Hen Transfer ionization: p + He H + He +e ++

We suppose that hydrogen is in its the ground state. Projectile proton energies are above 300 keV Scattering angles are of fractions of mrad

.


Contents


General formulas: FBA, SBA, EWBA Charge transfer Transfer excitation Transfer ionization




Some details of calcs


Laboratory frame Very low scattering angles (a few mrad) ! Energy conservation



Momentum conservation


Consequences


Full definition of q



Immovable helium ion during the collision.


...Born approximation is, at least in atomic physics, often much better than it has any right to be. (J. D. Jackson, H. Schiff) The problem of charge transfer is, however, not adequately described by the PWBA... (C.D. Lin)


FBA


Exact representation of the amplitude

so called paraxial approximation for fast proton


Exact representation of the amplitude
Basis for SBA and EWBA


Integral representation of EWBA (eikonal)


Integral representation of the FBA


CALCULATIONS: Charge transfer
Hong-Keun Kim et al

Phys. Rev. A 85, 022707 (2012)





Powerful note

All helium wave functions, both correlated and of the HF type, practically give the same shape and peak height in its vicinity for all considered energies






These calculations destroy the myth on the
dominant role of the Thomas Ne mechanism at bigger scattering angle. All SBA terms contribute at more or less equal footing, especially the Thomas ee mechanism



CALCULATIONS: Transfer excitation





Powerful notes

1. We can differ correlated and non-correlated wave functions in the vicinity of main peak. 2. We see definite boundaries for the proton energy, when FBA is valid.


CALCULATIONS: Transfer ionization, non-fixed plains


Ep = 630 keV


Ep = 630 keV, strongly correlated function


Ep = 630 keV, weakly correlated function


Ep = 300 keV


Ep = 300 keV, strongly correlated function


Ep = 300 keV, weakly correlated function


Ep = 300 keV, two strongly correlated functions. SBA is needed for forward direction, A2 is not enough


Ep = 300 keV, two strongly correlated functions. SBA is needed for forward direction, A2 is not enough


CALCULATIONS: Transfer ionization, fixed plains




Powerful note

1. Correlations in the initial wave functions play again very important role. 2. SBA considerably contributes to the forward scattering of the ejected electron (sequential mechanism). Backward scattering is the domain of shake-off mechanism.



Final conclusions
1. PWFBA is mainly responsible for the formation of differential cross sections near the main peak (OBK) 2. Correlations in the helium wave function play very important role when the residual target ion stays in its exciting (continuum) state.


Final conclusions
3. PWFBA forms the total cross section in a wide domain of energies.

4. The energy and angular range of validity of the PWFBA is rather narrow and decreases rapidly depending on the quantum state of the residual ion.


List of publications








Yu. V. Popov, O. Chuluunbaatar, S. I. Vinitsky, L. U. Ancarani, C. Dal Cappello, and P. S. Vinitsky. "Theoretical investigation of the p + He => H + He+ and p + He => H + He++ + e reactions at very small scattering angles of hydrogen" JETP 95 (2002), 620. P.S.Vinitsky, Yu.V.Popov , O.Chuluunbaatar. "Fast proton hydrogen charge exchange reaction at small scattering angles". Phys. Rev. A 71 (2005), 12706. S. Houamer, Y. Popov , C. Champion and C. Dal Cappello. "Charge transfer in collision of protons with water vapor at high projectile energies and small scattering angles: first Born approximation", Nucl. Instr. and Meth. B 267 (2009), 802 S. Houamer, Yu. V. Popov, and C. Dal Cappello. "Total cross sections for charge transfer reactions of protons with atomic and molecular targets at high projectile energies : The role of inner orbitals", Phys. Lett. A 373 (2009), 4447.


List of publications








Yu. V. Popov, O. Chuluunbaatar, V. L. Shablov, and K. A. Kouzakov. "Multiple ionization processes involving fast charged particles" Physics of Particles and Nuclei 41 (2010), 543 S. Houamer, Yu.V. Popov, C. Dal Cappello. "Failure of the multiple peaking approximation for fast capture processes at mrad scattering angles", Phys. Rev. A 81 (2010), 032703 Hong-Keun Kim,_ M. S. Schoeffler, S. Houamer, O. Chuluunbaatar, J. N. Titze, L. Ph. H. Schmidt, T. Jahnke, H. Schmidt-Boecking, A. Galstyan, Yu. V. Popov, and R. Doerner. "Electron transfer in fast proton-helium collisions", Phys. Rev. A 85 (2012) , 022707 S. Houamer, Yu.V. Popov. "Comment on "Four-body charge transfer processes in proton-helium collisions"", J. Phys. B: At.Mol.Opt.Phys. 46 (2013), 028001


List of publications






M. S. Schoeffler, O. Chuluunbaatar, Yu. V. Popov, S. Houamer, J. Titze, T. Jahnke, L. Ph. H. Schmidt, O. Jagutzki, A. G. Galstyan, and A. A. Gusev. "Transfer ionization and its sensitivity to the ground-state wave function", Phys. Rev. A 87 (2013), 032715 M. S. Schoeffler, O. Chuluunbaatar, S. Houamer, A. Galstyan, J. N. Titze, L. Ph. H. Schmidt, T. Jahnke, H. Schmidt-Boecking, Yu. V. Popov, R. Doerner, A.A. Gusev, and C. Dal Cappello. "2D momentum distribution of electron in transfer ionization of helium atom by fast projectile proton", Phys.Rev. A 88 (2013), 042710 M. S. Schoeffler, H.-K. Kim, O. Chuluunbaatar, S. Houamer, A.G. Galstyan, J. N. Titze, T. Jahnke, L. Ph. H. Schmidt, H. Schmidt-Boecking, R. Doerner, Yu. V. Popov, and A. A. Bulychev. "Transfer excitation reactions in fast proton-helium collisions", Phys. Rev. A 89 (2014), 032707


List of publications



Yu.V. Popov, V.L. Shablov, K.A. Kouzakov, and A.G. Galstyan. Comment on ``Dynamics of transfer ionization in fast ion-atom collisions'', Phys.Rev. A 89 (2014), 036701



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U Chowdhury et al. J. Phys. B: At. Mol. Opt. Phys. 45 (2012) 035203 144 times of difference with the experiment for Ep=300 keV !!!