Rami Ali 1 , Derar Mallah 1 and Feras Afaneh 2 1 Department of - PowerPoint PPT Presentation

Experimental Studies of the Energy Dependence of State-Selective Non-Dissociative Single Electron Capture in He 2+ on H 2 Collisions Rami Ali 1 , Derar Mallah 1 and Feras Afaneh 2 1 Department of Physics, The University of Jordan, Jordan 2 Physics Department, The Hashemite University, Jordan IAEA Technical Meeting on Uncertainty Assessment and Benchmark Experiments for Atomic and Molecular Data for Fusion Applications 19-21 December 2016

Smallness of capture to n = 1

Cold Target Recoil Ion Momentum Spectroscopy (COLTRIMS) Q ≈ − (𝑸 𝒎𝒑𝒐𝒉 𝒘 + 𝒋𝒘 𝟑 /𝟑)

Scattered He + projectile ions (150 keV He 2+ + H 2 )

We are truly looking at non-dissociative SEC No assumptions No indirect inferences ?

15 500 He He All SEC: 87.2% 400 SEC:86.6% 10 MEC:12.8% MEC:13.4% 3 300 x10 200 5 100 0 0 Ne All Ne 900 SEC: 54.4% SEC:57.9% 3 MEC:45.6% Counts MEC:42.1% 4 600 x10 2 300 1 0 0 Ar Ar All SEC: 46.5% 800 SEC:45.9% 10 MEC:53.5% MEC:54.1 4 600 x10 400 5 200 0 0 0 100 200 300 400 500 800 1200 1600 2000 X-ray energy (eV) TOF (CH#)

• Radiative decays of doubly excited states have been discussed for over two decades. • Not a single charge exchange x-ray spectral model has invoked the ATR mechanism or direct radiative decays. • A serious disconnect not only between the atomic physics and spectral modeling communities. For the Ne 8+ (4l,4 l’) doubly excited states the authors did not consider the radiative stabilization of these states at all and stated: “ The two-electron capture to the n = 4 shell, however, does not considerably (if at all) contribute to the radiative cascade producing the n = 4 x-ray spectra due to the predominant Auger decay of the doubly excited (4l,4l  ) state. ”