MEASUREMENTS OF POSITIVE ION/MOLECULE
REACTIONS INVOLVING SILICON
A. Ahmed and D.K. Bohme
Ion Chemistry Laboratory
Centre for Research in Mass Spectrometry
Centre for Research in Earth and Space Science
DEPARTMENT OF CHEMISTRY
YORK UNIVERSITY
This is a compilation of rate constants and product distributions for positive
ion/molecule reactions involving silicon which have been measured with the
selected-ion flow tube technique in the Ion Chemistry Laboratory at York
University up to 1999.
1
EXPLANATION OF TABLE
The table is ordered according to the molecular weight of the reactant ion in
the chemical equation. When reactant ions are the same, the reactions are ordered
according to the neutral reactant. This latter procedure is based upon counting the
number of carbon and hydrogen atoms in the neutral reactant. First priority is given
to the number of carbon atoms. The greater the number of carbon atoms, the
further down the table the neutral will appear. Within groups of neutrals containing
the same number of carbon atoms, the order is determined by the number of
hydrogen atoms. If the molecules contain the same number of hydrogen atoms,
then the order is dependent alphabetically on the remaining atoms in the neutral.
Neutral reactants that do not contain carbon atoms are ordered alphabetically with
the earliest letter taking precedence, and precede carbon-containing molecules. In
cases where the early letter is the same, the ordering is done by molecular weight
with the lower molecular weight taking precedence.
The collision rate constants included in the tabulation, kc, are derived using
the combined variational transition-classical trajectory treatment of T. Su and W.J.
Chesnavich, J. Chem. Phys., 76, 5183 (1982). Rate constants are presented in units
of 10-9 cm3 molecule-1s-1 and are either bimolecular or pseudo-bimolecular.
Reactions leading to association were not investigated as a function of total
pressure. The experiments were conducted as 2962K using the SIFT technique in
a helium buffer gas at ca. 0.35 Torr or 1.15 x 1016 helium atoms cm-3.
2
ION/NEUTRAL REACTION
Si+(2P) + CH2CCH2
Si+(2P) + CH3CCH
Si+(2P) + CH3CN
Si+(2P) + CH3COOH
Si+(2P) + CH3OH
Si+(2P) + CH3NH2
Si+(2P) + (CH3)2 CO
BR
kexp
kc
REF
1.2
1.4
10
1.2
1.7
10
2.4
4.49
3
3.0
2.3
1
2.2
2.4
1
1.2
2.03
2
0.28
3.40
6

SiC3H3+ + H
0.70

SiC2H+ + CH3
0.20

SiCH2+ + C2H2
0.10

SiC3H3+ + H
0.60

SiC2H+ + CH3
0.25

SiCH2+ + C2H2
0.15

CH2Si+ + CHN
0.5

C2H3NSi+
0.5

SiOH+ + CH3CO
0.70

CH3CO+ + SiOH
0.30

SiOH+ + CH3
0.75

SiOCH3+ + H
0.25

SiNH2+ + CH3
0.55

CH2NH2+ + SiH
0.35

SiNHCH3+ + H
0.10

SiOH+ + C3H5
0.45

CH3CO+ + SiCH3
0.30

C3H6+ + SiO0.25
3
ION/NEUTRAL REACTION
BR
kexp
kc
REF
0.60
1.2
1.82
2
0.98
1.64
2

CH2NHCH3+ + SiH

(SiNH2+ + C2H5)

SiNHCH3+ + CH3
0.35

SiN(CH3)2+ + H
0.05

CH2N(CH3)2+ + SiH
0.80

CH2NHCH3+ + SiCH3
0.09

(SiNH2+ + C3H7)

SiN(CH3)2+ + CH3
0.07

SiCH2+ + (CH3)2NH
0.04

(CH3CNH+ + SiCH5)
Si+(2P) + CH4

SiCH4+
1.0
0.0005
Si+(2P) + CH4

Si+.CH4
1.0
0.0005
Si+(2P) + CO

no reaction
Si+(2P) + CO2

SiCO2+
1.0
<0.00017
0.92
5
Si+(2P) + COS

SiS+ + CO
1.0
0.90
1.43
5
Si+(2P) + CS2

SiCS2+
1.0
0.066
1.47
5
Si+(2P) + C2H2

SiC2H+ + H
0.70
0.35
1.16
6,10

SiC2H2+
0.30

SiC2H+ + H
0.7

SiC2H2+
0.3
Si+(2P) + (CH3)2NH
Si+(2P) + (CH3)3N
Si+(2P) + C2H2
10
1.17
<0.00002
6,10
1,9
0.35
9
4
ION/NEUTRAL REACTION
BR
kexp
kc
REF
0.60
0.56
1.3
10

SiC2H4+

SiC2H3+ + H0.40
Si+(2P) + C2H5OH

SiOH+ + C2H5
1.0
2.5
2.4
1
Si+(2P) + C2H6

SiCH3+ + CH3
0.8
0.80
1.3
10

SiCH2+ + CH4
0.15

SiC2H4+ + H2
0.03

SiC2H6+
0.02

CNSi+ + CN0.55
0.55
0.15
3

C2N2Si+
0.45
Si+(2P) + C4H2

C4H+ + SiH
1.0
1.6
1.35
Si+(2P) + C6H6

(SiC6H6)+
1.0
observed
9
Si+(2P) + C10H8

(SiC10H8)+
0.9
observed
8

C10H8+ + Si
0.1
Si+(2P) + D2

no reaction
Si+(4P) + D2

SiD+ + D
Si+(2P) + HCN

Si+(2P) + C2H4
Si+(2P) + C2N2
6,9
<0.0001
1.1
1,9
1.0
0.77
1.1
1
CHNSi+
0.8
0.0070
3.75
3

CNSi+ + H
0.2
Si+(2P) + HCOOH

SiOH+ + CHO
1.0
2.3
1.9
1
Si+(2P) + HC2CN

C2HSi+ + CN
0.7
1.4
4.07
3

C3HNSi+
0.3

no reaction
<0.0002
1.5
1,9
Si+(2P) + H2
5
ION/NEUTRAL REACTION
BR
kexp
kc
REF
Si+(2P) + H2O

SiOH+ + H
1.0
0.23
2.1
1,9
Si+(2P) + NH3

SiNH2+ + H
1.0
0.64
2.41
2,9
Si+(2P) + NO

SiNO+
1.0
<0.01
0.85
5
Si+(2P) + NO2

SiO+ + N2
0.68
0.86

NO+ + SiO
0.30

SiNO2+
0.02
Si+(2P) + N2O

SiO+ + N2
1.0
0.40
Si+(2P) + O2

SiO2+
1.0
<0.0001
Si+(2P) + SO2

SO+ + SiO
1.0
0.81
1.96
5
SiCH2+ + CH2CCH

SiC3H3+ + CH3
0.95
0.61
1.3
10

SiC4H5+ + H
0.05

SiC3H3+ + CH3
0.85
0.91
1.5
10

SiC4H5+ + H
0.15
SiC2H+ + CH2CCH2

SiC5H5+
1.0
0.56
1.2
10
SiC2H+ + CH3CCH

SiC5H5+
1.0
0.65
1.4
10
SiC2H+ + C2H2

SiC4H3+
0.9
0.2
1.0
6

SiC4H+ + H20.1
SiC2H2+ + C2H2

SiC4H4+
1.0
0.2
SiC2H4+ + C2H4

SiC2H3+ + C2H5
0.8
0.40
1.1
10

SiC4H8+
0.2

products
1.0
0.077
1.1
10
SiCH2+ + CH3CCH
SiC2H4+ + C2H6
5
1.07
5
5,9
10
6
ION/NEUTRAL REACTION
BR

SiNH2+ + C3H4

SiC3H3+.NH3
SiC6H6+ + CO

no reaction
SiC6H6+ + C2H2

SiC6H6+.C2H2

SiC8H7+ + H0.4

SiC4H2+ + C6H6
>0.3

SiC6H6+.C4H2
<0.70
SiC6H6+ + D2

no reaction
SiC6H6+ + H2O

SiC6H6+.H2O
0.4

C6H6+ + (SiOH2)
0.35

C6H7+ + SiOH
0.25
SiC6H6+ + NH3

SiC6H6+.NH3
1.0
SiC6H6+ + N2

no reaction
SiC6H6+ + O2

C6H6+ + (SiO2)
0.9

C6H6O+ + SiO
0.1
SiC10H8+ + D2

no reaction
SiC10H8+ + H2O

C10H8+ + (SiOH2)
SiC10H8+ + NH3

SiC10H8+.NH3
SiC10H8+ + N2

no reaction
SiC10H8+ + O2

C10H8+ + (SiO2)
SiC10H8+ + CO

no reaction
SiC3H3+ + NH3
SiC6H6+ + C4H2
0.6
kexp
kc
REF
0.72 (0.66)
2.1
10
<0.00009
0.73
9
0.06
0.94
9
9
0.70
0.98
9
14
<0.0003
1.1
9
0.20
2.0
9
0.39
2.0
9
<0.0002
9
0.003
0.60
9
<0.00035
1.1
9
1.0
0.0055
2.2
9
1.0
0.41
2.0
9
<0.0004
0.63
8,9
0.00037
0.58
8,9
<0.00031
0.70
9
1.0
7
ION/NEUTRAL REACTION
BR
kexp
kc
REF
0.063
0.91
8,9
1.0
0.93
8,9
1.0
8

C10H8+ + (SiC2H2)
0.9

(SiC10H8+.C2H2)
0.1
SiC10H8+ + C4H2

C10H8+ + (SiC4H2)
1.0
SiC10H8+ + C6H6

no reaction
<0.0006
SiF+ + CO

no reaction
< 0.0001
SiF2.+ + CO

SiF2CO+
1.0
0.00036
7.6
13
SiF2CO.+ + CO

SiF2(CO)2.+
1.0
0.00020
7.3
13
SiF3+ + CO

SiF3CO+
1.0
0.041
7.4
11,13
SiF3(CO)+ + CO

SiF3(CO)2+
1.0
0.00041
7.1
13
SiF+ + NH3

No Reaction
<0.001
22
14
SiF2+ + NH3

NH3+ + SiF2
8.0
21
14
SiF3+ + NH3

F2SiNH2+ + HF
4.9
21
14
F2SiNH2+ + NH3

FSi(NH2)2++HF
5.3
21
14

F2Si(NH2)NH3+

NH4++ F2SiNH

HSiO2+
0.005
0.76
12

SiOH+ + O

HSiO+ + O

SiOH+ + CO
0.19
0.91
12

HCO+ + SiO

SiOH+ + N2
0.56
1.0
12

HSiO+ + N2
SiC10H8+ + C2H2
SiH+ + O2
SiH+ + CO2
SiH+ + N2O
13
8
SiH+ + SO2

SiOH+ + SO
SiNH2+ + H2

no reaction
SiNH2+ + NH3

NH4+ + SiNH
SiNH2+ + CO

no reaction
SiNH2+ + CH3NH2

CH3NH3+ + SiNH
ION/NEUTRAL REACTION
1.0
1.2
1.9
<0.00034
1.0
12
2
0.58, 0.90
2.24
<0.0002
2,7
2
1.0
1.0
1.83
2
BR
kexp
kc
REF
1.5
2.1
7
2.4
3.0
7

CH2SCH3+ + (SiNH3)
0.70

SiNH2+.(CH3)2S
0.25

CH4NSi+ + CH3SH
0.05

CH4NSi+ + (C2H4O)
0.85

SiNH2+.(CH3)2CO
0.15
SiO+ + N2O

SiO2+ + N2
1.0
0.48
0.89
5
SiO+ + NO2

NO+ + SiO2
0.63
1.5
0.94
5

NO2+ + SiO
0.35

SiO2+ + NO
0.02
SiO+ + O2

no reaction
<0.0002
0.69
5
SiOH+ + H2

no reaction
<0.0002
1.5
1
SiOH+ + H2O

SiH3O2+
1.0
0.01
2.5
1
SiOH+ + H2S

SiOH+.H2S
1.0
<0.001
1.5
4
SiOH+ + NH3

NH4+ + SiO
1.0
2.5
2.2
4
SiOH+ + CO

SiOH+.CO
1.0
<0.0003
0.82
1
SiOH+ + HCOOH

SiH3O2+ + CO
>0.9
1.0
1.7
1
SiNH2+ + (CH3)2S
SiNH2+ + (CH3)2CO
9
SiOH+ + CH3OH
SiOH+ + CH3CN

SiOH+.HCOOH
<0.1

SiOCH3+ + H2O
0.90

SiOH+.CH3OH
0.10

SiOH+.CH3CN
0.55

CH3CNH+ + SiO
0.45
ION/NEUTRAL REACTION
1.15
2.1
1
0.48
4.0
4
BR
kexp
kc
REF
2.3
2.0
1
2.4
2.1
1
0.95
1.8
4

CH3CO+ + (SiH2O2)
0.90

CH3COOH2+ + SiO
0.10

SiH3O2+ + C2H4
0.60

SiOC2H5+ + H2O
0.30

C2H5OH2 + SiO
0.07

SiH3O+ + C2H4O
0.03

SiOH+.(CH3)2O
0.8

(CH3)2OH+ + SiO
0.2

SiOH+.C3H4 0.8
0.031
1.2
4

C3H5+ + SiO0.2

CH3NH3+ + SiNH
1.0
1.3
1.74
2
(CH3)2NH2+ + SiNCH3
0.95
0.7
1.50
2

SiNHCH3+(CH3)2NH
0.05
SiS+ + H2

no reaction
>0.00002
1.52
5
SiS+ + O2

SO+ + SiO
0.70
0.089
0.65
5

SiO+ + SO
0.30
SiOH+ + CH3COOH
SiOH+ + C2H5OH
SiOH+ + (CH3)2O
SiOH+ + H2CCCH2
SiNHCH3+ + CH3NH2
SiNHCH3+ + (CH3)2NH 
10
SiS+ + CO

no reaction
SiS+ + COS

SiS2+ + CO
SiSH+ + H2O

SiSH+ + H2S
SiSH+ + NH3
<0.00004
0.78
5
1.0
1.4
1.14
5
SiOH+ + H2S
1.0
1.1
2.4
4

H3S+ + SiS
1.0
0.29
1.4
4

NH4+ + SiS
1.0
0.97
2.2
4
BR
kexp
kc
REF
ION/NEUTRAL REACTION
SiSH+ + HCN

HCNH+ + SiS
1.0
0.61
1.6
4
SiSH+ + C2H4

SiSH+.C2H4
1.0
0.018
1.1
4
SiN(CH3)2+.(CH3)3N
1.0
0.85
1.26
2
SiN(CH3)2+ + (CH3)3N 
11
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+
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2.
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3.
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4.
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5.
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6.
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9.
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10.
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11.
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12.
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13.
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14.
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12