Supporting Information for TCAC-D-11-00076

Supporting Information for TCAC-D-11-00076

Facial Dissociations of Water Molecules on the Outside and Inside of Armchair Single-Walled Silicon Nanotubes: Theoretical Predictions from Multilayer Quantum Chemical Calculations

Yong Wang,1,2 Guoyong Fang,1 Jing Ma*,1and Yuansheng Jiang1

1Institute of Theoretical and Computational Chemistry, Key Laboratory of Mesoscopic Chemistry of MOE, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing, 210093, P. R. China; Fax:(86)25-83596131; Phone: (86)25-83597408; Email:

2College of Chemistry, Chemical Engineering and Material Science,SoochowUniversity, Su Zhou, 215123, China

A List of Contents...... S1

Table S1.The Relative Barrier Energies (Ea)and Binding Energies (Eb) of DissociationAdsorption Reactions of H2O with Interior (in) and Exterior (out) Sidewallsof SiNTs by the Simplified Fragment Embedding Calculations ...... S2

Table S2. Important Structural Parameters and the Relative Energies for the Int, TS, and Pr of DissociativeAdsorption of H2O to the Sidewalls of Armchair SiNTs at the level of B3LYP/LanL2dzand ONIOM (B3LYP/6-31G*: B3LYP/LanL2dz)………………………………………………….S3

Table S3. The Imaginary Frequency (in units of cm-1) of Transition State (TS) of Dissociation Adsorption Reactions of H2O with Interior (in) and Exterior (out) Sidewalls of (4, 4) and (5, 5) SiNTsfor Cluster II Obtained by the Simplified Fragment-Embedding, ONIOM,and Full B3LYP/LanL2DZCalculations.……………………………………………..…………..S4

Table S4.Average Computing Time for Frequency Analysis of Dissociative Adsorption of Water to Si(5, 5) Nanotube, Costed byFragment Embedding, ONIOM, and Full QM Calculationson Inspur Workstation with 4 CPUs and 3GB RAM Per Processor ..…………....…………..S4

Table S5.Binding Energies (Eb) of one H2O Adsorbedon the Interior (in) and Exterior (out) Sidewallsof SiNTs by the Simplified Fragment Embedding Calculations at the Level of B3LYP/LanL2dz.………………...... S5

Table S6.The Relative Barrier Energies (Ea)and Exothermic Energies (Eexo) of DissociationAdsorption Reactions of H2O with Interior (in) and Exterior (out) Sidewallsof SiNTs by the ONIOM Methods (in units of kcal/mol).………………………..……………………………………S5

Figure S1. Optimized geometries of stationary points along the reaction pathway of dissociation of H2Oonthe (4, 4) armchair single-walledSiNTs by usingFragmentation method (CASSCF(4,4)/6-31G**: B3LYP/LanL2dz)...... S6

Figure S2. Optimized geometries of stationary points along the reaction pathway of dissociation of H2Oonthe (4, 4) and (5, 5) armchair single-walledSiNTs by using ONIOM(B3LYP/6-31G*: B3LYP/STO-3g)...... S7

Total:6 pages

Table S1. The Relative Barrier Energies (Ea)and Exothermic Energies (Eexo) of DissociationAdsorption Reactions of H2O with Interior (In) and Exterior (Out) Sidewallsof SiNTs Predicted by the Simplified Fragment Embedding Calculations at the level of B3LYP/6-311+G**//B3LYP/6-31G* (in units of kcal/mol).

SiNT / Activation / Exothermic
In-Ea / Out-Ea / In-Eexo / Out-Eexo
Cluster I(B3LYP/6-311+G**//B3LYP/6-31G*): Bulk Model (B3LYP/LanL2dz)
Si(4,4) / 34.06 / 10.34 / -16.55 / -45.39
Si(5,5) / 15.02 / 5.40 / -22.47 / -17.12
Si(6,6) / 21.11 / 4.25 / -19.61 / -23.95
Si(7,7) / 22.44 / 9.58 / -18.97 / -21.18
Si(8,8) / 20.44 / 11.47 / -16.98 / -20.24
Si(9,9) / 18.01 / 15.00 / -18.23 / -20.00
Si(10,10) / 21.23 / 13.71 / -17.77 / -24.88
Cluster II (B3LYP/6-311+G**//B3LYP/6-31G*): Bulk Model (B3LYP/LanL2dz)
Si(4,4) / 17.69 / 12.42 / -1.53 / -22.62
Si(5,5) / 17.45 / 11.94 / -3.73 / -23.70
Si(6,6) / 18.98 / 10.58 / -7.09 / -20.07
Si(7,7) / 16.82 / 14.17 / -13.29 / -19.28
Si(8,8) / 18.49 / 12.07 / -11.47 / -19.08
Si(9,9) / 18.29 / 11.84 / -12.05 / -18.10
Si(10,10) / 19.41 / 11.48 / -12.43 / -18.61
Cluster III (B3LYP/6-311+G**//B3LYP/6-31G*): Bulk Model (B3LYP/LanL2dz)
Si(4,4) / 19.60 / 12.15 / -6.31 / -23.24
Si(5,5) / 20.45 / 11.14 / -11.01 / -21.05
Si(6,6) / 18.53 / 12.92 / -8.27 / -20.72
Si(7,7) / 22.64 / 13.24 / -10.55 / -17.03
Si(8,8) / 21.08 / 12.30 / -13.79 / -19.23
Si(9,9) / 17.77 / 10.83 / -13.22 / -17.02
Si(10,10) / 20.90 / 10.96 / -13.38 / -16.03

SiNTs / B3LYP/LanL2dz / ONIOM (B3LYP/6-31G*: B3LYP/LanL2dz)
Cluster I / ONIOM (B3LYP/6-31G*: B3LYP/LanL2dz)
Cluster II
bond lengths (Å) / E
(kcal/mol) / bond lengths (Å) / E
(kcal/mol) / bond lengths (Å) / E
(kcal/mol)
Si–Si / Si–O / Si…H / O…H / Si–Si / Si–O / Si…H / O…H / Si–Si / Si–O / Si…H / O…H
Si(4,4)
interior / Int / 2.357 / 2.103 / 2.365 / 0.980 / 0.00 / 2.358 / 2.125 / 3.475 / 0.978 / 0.00 / 2.352 / 2.128 / 3.464 / 0.977 / 0.00
TS / 2.340 / 1.845 / 1.763 / 1.331 / 25.14 / 2.355 / 1.844 / 1.832 / 1.311 / 21.44 / 2.355 / 1.848 / 1.827 / 1.320 / 20.25
Pr / 2.330 / 1.731 / 1.488 / 2.455 / 10.06 / 2.354 / 1.691 / 1.500 / 2.541 / -4.51 / 2.344 / 1.693 / 1.505 / 2.613 / -10.31
Si(4,4)
exterior / Int / 2.355 / 2.016 / 2.954 / 0.982 / 0.00 / 2.368 / 2.081 / 2.909 / 0.980 / 0.00 / 2.364 / 2.083 / 2.903 / 0.980 / 0.00
TS / 2.449 / 1.855 / 1.810 / 1.263 / 7.76 / 2.426 / 1.857 / 1.826 / 1.265 / 8.28 / 2.421 / 1.856 / 1.820 / 1.274 / 8.74
Pr / 2.409 / 1.733 / 1.485 / 2.900 / -16.07 / 2.404 / 1.693 / 1.493 / 2.984 / -27.15 / 2.402 / 1.693 / 1.494 / 2.972 / -25.78
Si(5,5)
interior / Int / 2.332 / 2.142 / 3.408 / 0.978 / 0.00 / 2.348 / 2.158 / 3.600 / 0.977 / 0.00 / 2.342 / 2.178 / 3.589 / 0.976 / 0.00
TS / 2.338 / 1.848 / 1.774 / 1.322 / 22.92 / 2.363 / 1.830 / 1.838 / 1.342 / 20.01 / 2.363 / 1.834 / 1.832 / 1.347 / 19.31
Pr / 2.348 / 1.736 / 1.492 / 2.854 / 5.52 / 2.366 / 1.698 / 1.502 / 2.870 / -7.91 / 2.369 / 1.698 / 1.504 / 2.913 / -9.44
Si(5,5)
exterior / Int / 2.343 / 2.037 / 2.963 / 0.982 / 0.00 / 2.366 / 2.092 / 2.909 / 0.980 / 0.00 / 2.361 / 2.095 / 2.910 / 0.980 / 0.00
TS / 2.445 / 1.855 / 1.797 / 1.273 / 8.99 / 2.426 / 1.856 / 1.818 / 1.272 / 8.90 / 2.422 / 1.854 / 1.813 / 1.280 / 9.45
Pr / 2.407 / 1.735 / 1.486 / 2.855 / -12.97 / 2.406 / 1.693 / 1.494 / 2.930 / -24.67 / 2.403 / 1.693 / 1.494 / 2.920 / -23.31

Table S3.The Imaginary Frequency (in units of cm-1) of Transition State (TS) of Dissociation Adsorption Reactions of H2O with Interior (In) and Exterior (Out) Sidewalls of (4, 4) and (5, 5) SiNTsfor Cluster II Obtained by the Simplified Fragment-Embedding, ONIOM,and Full B3LYP/LanL2DZCalculations.

Methods / Si(4, 4) / Si(5, 5)
In-TS / Out-TS / In-TS / Out-TS
B3LYP/LanL2dz / 1309.39i / 1296.79i / 1354.07i / 1303.75i
Fragment
(B3LYP/6-31G*:B3LYP/LanL2dz) / 1453.95i / 1480.54i / 1472.55i / 1480.54i
ONIOM
(B3LYP/6-31G*:B3LYP/LanL2dz) / 1512.14i / 1479.79i / 1490.12i / 1503.97i

Table S4.Average Computing Time for Frequency Analysis of Dissociative Adsorption of Water to Si(5, 5) Nanotube,Costed byFragment Embedding, ONIOM, and Full QM Calculationson Inspur Workstation with 4 CPUs and 3GB RAM Per Processor.

Methods / CPU time
Active part:Cluster I (Si16 fragment)
Fragment (B3LYP/6-31G*:B3LYP/LanL2dz) / ~2.5 hours
ONIOM(B3LYP/6-31G*: B3LYP/Lanl2dz) / ~30 hours
ONIOM(B3LYP/6-31G*: B3LYP/STO-3g) / ~14 hours
ONIOM(B3LYP/6-31G*: AM1) / ~11 hours
Active part: Cluster II (Si30 fragment)
Fragment(B3LYP/6-31G*:B3LYP/LanL2dz) / ~20 hours
ONIOM(B3LYP/6-31G*: B3LYP/Lanl2dz) / ~40 hours
Full QM(B3LYP/Lanl2dz) / ~99 hours

Table S5. Binding Energies (Eb) of a Single H2O Molecule Adsorbedon the Interior (In) and Exterior (Out) Sidewallsof SiNTs by the Simplified FragmentEmbedding Calculations at the Level of B3LYP/LanL2dz.

SiNTs / Diameter, Å / r(Si…O), Å / Eb, kcal/mol
In / Out / In / Out
Si(4,4) / 8.62 / 2.103 / 2.016 / 5.20 / 11.09
Si(5,5) / 11.02 / 2.145 / 2.037 / 3.88 / 8.31
Si(6,6) / 13.04 / 2.205 / 2.053 / 2.97 / 5.88
Si(7,7) / 15.36 / 2.271 / 2.072 / 2.24 / 4.54
Si(8,8) / 17.42 / 2.331 / 2.089 / 1.81 / 3.54
Si(9,9) / 19.71 / 2.393 / 2.112 / 1.50 / 2.63
Si(10,10) / 21.80 / 2.448 / 2.130 / 1.28 / 1.55

Table S6. The Relative Barrier Energies (Ea)and Exothermic Energies (Eexo) of DissociationAdsorption Reactions of H2O with Interior (In) and Exterior (Out) Sidewallsof SiNTs by the ONIOMMethods (in units of kcal/mol).

SiNT / Activation / Exothermic
In-Ea / Out-Ea / In-Eexo / Out-Eexo
ONIOM(B3LYP/6-31G*: B3LYP/STO-3g)
Si(4,4) / 13.17 / 7.19 / -6.12 / -25.65
Si(5,5) / 16.68 / 8.29 / -10.10 / -23.61
Si(6,6) / 18.55 / 12.43 / -13.34 / -21.83
Si(7,7) / 21.17 / 12.86 / -10.79 / -20.80
Si(8,8) / 21.70 / 13.32 / -10.92 / -20.80
Si(9,9) / 21.90 / 13.48 / -11.21 / -19.93
Si(10,10) / 21.80 / 13.70 / -11.46 / -19.69
ONIOM(B3LYP/6-31G*: AM1)
Si(4,4) / 21.35 / 6.53 / -12.00 / -28.59
Si(5,5) / 21.24 / 7.55 / -7.42 / -28.26
Si(6,6) / 16.69 / 8.21 / -15.55 / -26.11
Si(7,7) / 16.75 / 8.55 / -10.82 / -25.38
Si(8,8) / 15.99 / 8.84 / -14.43 / -24.79
Si(9,9) / 16.72 / 9.05 / -12.29 / -24.47
Si(10,10) / 15.98 / 9.23 / -17.25 / -24.19

Figure S1. Optimized geometries of stationary points along the reaction pathway of dissociation of H2Oonthe (4, 4) armchair single-walledSiNT by usingfragment (CAS(4,4)/6-31G**:B3LYP/LANL2DZ): (a) for internal and (b) for external reactions

Figure S2.Optimized geometries of stationary points along the reaction pathway of dissociation of H2Oonthe (4, 4) and (5, 5) armchair single-walledSiNTs by usingONIOM(B3LYP/6-31G*: B3LYP/STO-3g): (a) for internal and (b) for external reactions