EII of plasma edge constituents properties of Bex
EII of plasma edge constituents, properties of Bex. HS. y. Matejcik, molecules P. Mach, J. Urban Comenius University Bratislava Slovakia
Bratislava
Overview - Appearance energies of C 2 D 6 - Cross section for EII to propane - Be. H and Be. H 2 – structure and energies - Structure and energetics of Bem. Hn clusters
Electron impact ionization n n n cross sections (total, partial) ionization energies appearance energies kinetic energy release gas temperature dependencies products of the reactions
Experimental setup
Cross section measurements n Absolute measurement of the pressure n Relative flow technique n Ar as a calibration gas
Threshold behaviour of the cross sections Atoms: Wannier theory: w(E, A, d) = 0 A(E-IE)d d=1. 127 Fitting function: f(E, U) - EEDF E<AE E>AE
Threshold behaviour of the cross sections d=1. 127± 0. 01
Isotopic effect on AE CH 3 D AE (e. V) 293 K CD 4 AE (e. V) 293 K CH 4 AE (e. V) 293 K 12. 75 ± 0. 03 12. 89 ± 0. 03 12. 65 ± 0. 04 CH 4+ CH 2 D+ + H– 13. 66 ± 0. 07 CH 2 D+ + H 14. 42 ± 0. 05 14. 54 ± 0. 05 13. 58 ± 0. 1 14. 34 ± 0. 1 CH 3+ + H– CH 3+ + H CH 3 D+ Denifl et al. IJMS 248 (2005) 29
Isotopic shift Present me. V a) me. V (CH 3 D)+/CH 3 D 100 50 (CH 2 D)+/CH 3 D 80 (CH 3)+/CH 3 D 200 (CHD)+/CH 3 D 110 (CD 4)+/CD 4 190 (CD 3)+/CD 4 200 130 (CD 2)+/CD 4 310 90 170 b) me. V 160 a) F. P. Lossing, A. W. Tickner, W. A. Bryce, J. Chem. Phys. 19, 1254 (1951). b) V. H. Dibeler, M. Krauss, R. M. Reese, F. N. Harlee J. Chem. Phys. 42, 3791 (1965). Denifl et al. IJMS 248 (2005) 29
EII of C 2 D 6 e + C 2 D 6 → C 2 D 6+ + 2 e → C 2 D 5+ + D– + 2 e → C 2 D 2+ + 2 D 2 + e
EII to C 2 D 6
Izotopic effects in C 2 D 6 e + C 2 D 6 → AE (in e. V) Present Ethana ( C 2 D 6 ) + 11. 80 ± 0. 05 11. 46 ± 0. 06 ( C 2 D 5 ) + 11. 78 ± 0. 07 ? 12. 06± 0. 03 ( C 2 D 4 )+ 12. 09 ± 0. 08 11. 9± 0. 04 ( C 2 D 2 )+ 15. 06± 0. 2 15. 02± 0. 2 a. E. Vaseková, M. Stano, S. Matejcik, , J. D. Skalný, P. Mach, T. D. Märk, J. Urban Int. J. of Mass Spect. , 235 (2004) 155 -162
Grill et al. ZPhys. D 25 (1993) 217
EII to C 3 H 8
Appearance energies C 3 H 8 Denifl CPL 402 (2005) 80
EII to C 3 H 8 cross sections Exp: N. Duric, I. Čadež, M. Kurepa, Int. J. Mass Spectrom. & Ion Processes, 108 (1991) R 1 -R 10.
Total cross sections σBEB(12 e. V) σPresent(12 e. V) σExp(12 e. V) [10 -16 cm 2] 0. 119 0. 21 0. 35 Exp: N. Duric, I. Čadež, M. Kurepa, Int. J. Mass Spectrom. & Ion Processes, 108 (1991) R 1 -R 10. BEB: W. Hwang, Y. -K. Kim and M. E. Rudd, J. Chem. Phys. , 104 (1996) 2956
Cross sections at 700 K n n Not finnished yet Problems with contamination
EII to Bex. Hy n Experimental problems n Vaporisation only at T>1000°C n Toxicity of Be
Be. H dissoc. energy CCSDT-R 12 1 exc. energy 2Σ – 2Π, experiment 17086 cm-1 , theory – 17116 cm-1
Be. H bond lenght
Be. H 2 basis CCSD(T)R 12 CCSD(T) Full B 3 LYP Be. H 2 Be-H [A] TAEa) [e. V] DEBe+H 2 [e. V] Be: 19 s 14 p 8 d 6 f 4 g H: 9 s, 6 p, 4 d, 3 f 1. 3260 6. 418 1. 671 aug-cc-p. Cv. DZ 1. 3366 6. 108 1. 585 aug-cc-p. Cv. TZ 1. 3298 6. 321 1. 614 aug-cc-p. Cv. QZ 1. 3267 6. 391 1. 657 aug-cc-p. Cv 5 Z 1. 3263 6. 406 1. 664 6 -311++G(3 d, 3 p) 1. 3248 6. 741 1. 965 aug-cc-p. Cv 5 Z 1. 3239 6. 748 1. 964
Be. H 2 bond lenght
Ben. H clusters – MP 2
Ben. H 1
Be 3 Hn Be 4 Hn
Be 4 Hn
Futher plans n n n Propane cross section at high T C 2 D 6 – high T, cross sections Ionization energies of the Be compounds Appearance energies of the fragments Simulation of the Be surface Chemistry on the Be surface
n Thank you for your attention
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