Electron-Impact lonization Cross Sections for Polyatomic Molecules, Radicals, and Ions. Yong-Ki Kim and Karl K. Irikura

Transcription

1 Electron-Impact lonization Cross Sections for Polyatomic Molecules, Radicals, and Ions National Institute of Standards ong-ki Kim and Karl K. Irikura

2 dipole interaction between the incident and the target electrons. The dipole interaction is characteristic

3 molecular wave functions, while experimental values or results from correlated wave functions were used for outer valence orbitals. In Sec. we compare BEB cross sections to experimental data for neutral molecules, molecular ions,

4 experimental data.

5 cross sections

6 valence orbitals, Kim et al. [6] found an alternative to dividing u+l by w, i.e., take

7 dissociation of a molecular ion without ionizing any electron still produces an ion, the determination

8 dissociate

9 the BEB cross section for orbitals with B < 9 ev; inverted triangles, experimental data by Becker []; circles, experimental data

10 Table

11 3ai b aj 3b lb l 5aj Ia b 6a l B from CCSD(T) BF 3 le' la l' ai ' 3aj' e' a l' 3e' Ia " e' le" Ia ' B from CCSD(T) B from CCSD(T) B from CCSD(T) BC la a 3a In a 5a 6a 7C 7a s BC Ib la l b aj 3b 3aj lb l Ia b aj 5aj 6aj 5b 7a l

12 6b 8aj bj a 7b 9a l BC 3 le' lai e' aj' 3e' 3aj' le" Ia " e' Ia ' aj' 5aj' 5e' 6&i 6e' a " 7e' e" a f C H 3 (vinyl) C 3 H 3 (propargyl) la' a' 3a' a' 5a' 6a' la" 7a' laj aj 3aj a l 5a! 6aj 7a l Ib lb l b b! ,

13 C 3 H (allene) C 3 H 5 (allyl) laj Ib aj 3ai b aj 3b le e la l Ib a! 3aj b aj 5ai 3b b 6aj Ibi Ia B from CCSD(T) UHF (averaged) C 3 H (propyne) la l aj 3ai aj 5a t 6a t 7a l le e C 3 H 6 (propene) la' a' 3a' a ( 5a' 6a' 7a' 8a' la" 9a' loa a"

14 C H (diacetylene) C H (vinylacetylene) la g la u a g a u 3a g 3a u a o 0 U 5a g l7i g la a' 3a' a' 5a' 6a' 7a' 8a' 9a' 0a ( lla' la" a' a" C H 6 (transbutadiene) la g lb u a g b u 3a o 3b u a g b u 5b u 5a g 6a g 6b u 7a g la u lb g C H 8 (-butene) la a

15 3a a 5a 6a 7a 8a 9a loa lla a 3a a 5a 6a C H 8 (trans- -butene) la g lb u a g b u 3a o 3b u a 0 b u 5b u 5a o la u lb g 6b u 6a g 7a go a u C H 8 (isobutene) la l Ib aj 3aj aj b 5a l 6a! 3b 7ai lb l Ia ,

16 b 5b b, B from est. CCSD(T) CgH (triacetylene) log lo u o g o u 3a u 3o fc a g a u 5o g 5a u 6o g 6o u 7o 0 l7c g 7^ B from est. CCSD(T) C 6 H 6 (fulvene) laj a^ 3a l Ib b aj 5aj 6aj 3b 7ai b 8aj 9aj 5b 6b loaj llaj Ibj 7b b t Ia

17 (benzene) la lg le lu Ie g lb lu a lg e g 3a lg Ib u 3e lu Ia u 3e g le lg CF la a 3a a ITC 5a n CF Ib la l aj 3a l b a! 3b 5a t Ibj Ia b 6aj CF 3 le la l aj 3a l e a l 3e 5a l e

18 CF SiF 5e Ia 6a l < * aj 3a^ ^ aj 3t le t Itl la a 3a a In 5a 6a TC 7a 3n sp BfromCCSD(T) B from CCSD(T) B from CCSD(T) UHF (averaged) B partly from OVGF SiF * Ib aj 3* b lb l * 5*i 3b 6aj b 7a l bi * 5b 8aj SiF 3 * a l le

19 3aj e aj 5a 3e 6aj e 7a l 5e 6e Ia 8 ai SiF laj aj " 3& t aj 3t 5aj t le 5t ll l OH la (a) a(a) 3a(a) l7i(a) l7i(a) la(p) a(p) 3a(p) Irc(p) HO (hydroperoxyl) la (a) a' (a) 3a' (a) a f (a) 5a' (a) la" (a) 6a' (a) a" (a) 7a ( (a)

20 la' (P) a' (p) 3a'(p) a' (p) 5a'(P) 6a' (p) la" (P) 7a' (P) CH 0 (formaldehyde) * aj 3aj aj Ib 5a l lb l b CHO (formyl) la a' 3a' a' 5a' la" 6a' 7a' C H 3 O (vinoxyl) la a' 3a' a' 5a' 6a' 7a' 8a' 9a' la" 0a' a"

21 radicals. Except for fluorine-containing radicals, we find good to excellent agreement. For H, the BEQ cross section in Fig. is accurate enough to serve as the normalization standard for experiments. Comparisons of the BEB model to a large collection of molecules and some atoms are available from a public NIST web site:

22 [5] Tarnovsky,