Abstract
The heat of formation, ΔE, for silicon (111) surfaces terminated with increasing densities of the alkyl groups CH3- (methyl), C 2H5- (ethyl), (CH3)2CH- (isopropyl), (CH3)3C- (terf-butyl), CH3(CH 2)5- (hexyl), CH3(CH2) 7(octyl), and C6H5- (phenyl) was calculated using quantum mechanics (QM) methods, with unalkylated sites being H-terminated. The free energy, ΔG, for the formation of both Si-C and Si-H bonds from Si-Cl model componds was also calculated using QM, with four separate Si-H formation mechanisms proposed, to give overall ΔGs values for the formation of alkylated Si(111) surfaces through a two step chlorination/ alkylation method. The data are in good agreement with measurements of the packing densities for alkylated surfaces formed through this technique, for Si-H free energies of formation, ΔGH, corresponding to a reaction mechanism including the elimination of two H atoms and the formation of a C=C double bond in either unreacted alkyl Grignard groups or tetrahydrofuran solvent.
| Original language | English |
|---|---|
| Pages (from-to) | 14842-14848 |
| Number of pages | 7 |
| Journal | Journal of Physical Chemistry B |
| Volume | 110 |
| Issue number | 30 |
| DOIs | |
| Publication status | Published - Aug 3 2006 |
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ASJC Scopus subject areas
- Physical and Theoretical Chemistry
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Quantum mechanics calculations of the thermodynamically controlled coverage and structure of alkyl monolayers on Si(111) surfaces. / Nemanick, E. Joseph; Solares, Santiago D.; Goddard, William A.; Lewis, Nathan S.
In: Journal of Physical Chemistry B, Vol. 110, No. 30, 03.08.2006, p. 14842-14848.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Quantum mechanics calculations of the thermodynamically controlled coverage and structure of alkyl monolayers on Si(111) surfaces
AU - Nemanick, E. Joseph
AU - Solares, Santiago D.
AU - Goddard, William A.
AU - Lewis, Nathan S
PY - 2006/8/3
Y1 - 2006/8/3
N2 - The heat of formation, ΔE, for silicon (111) surfaces terminated with increasing densities of the alkyl groups CH3- (methyl), C 2H5- (ethyl), (CH3)2CH- (isopropyl), (CH3)3C- (terf-butyl), CH3(CH 2)5- (hexyl), CH3(CH2) 7(octyl), and C6H5- (phenyl) was calculated using quantum mechanics (QM) methods, with unalkylated sites being H-terminated. The free energy, ΔG, for the formation of both Si-C and Si-H bonds from Si-Cl model componds was also calculated using QM, with four separate Si-H formation mechanisms proposed, to give overall ΔGs values for the formation of alkylated Si(111) surfaces through a two step chlorination/ alkylation method. The data are in good agreement with measurements of the packing densities for alkylated surfaces formed through this technique, for Si-H free energies of formation, ΔGH, corresponding to a reaction mechanism including the elimination of two H atoms and the formation of a C=C double bond in either unreacted alkyl Grignard groups or tetrahydrofuran solvent.
AB - The heat of formation, ΔE, for silicon (111) surfaces terminated with increasing densities of the alkyl groups CH3- (methyl), C 2H5- (ethyl), (CH3)2CH- (isopropyl), (CH3)3C- (terf-butyl), CH3(CH 2)5- (hexyl), CH3(CH2) 7(octyl), and C6H5- (phenyl) was calculated using quantum mechanics (QM) methods, with unalkylated sites being H-terminated. The free energy, ΔG, for the formation of both Si-C and Si-H bonds from Si-Cl model componds was also calculated using QM, with four separate Si-H formation mechanisms proposed, to give overall ΔGs values for the formation of alkylated Si(111) surfaces through a two step chlorination/ alkylation method. The data are in good agreement with measurements of the packing densities for alkylated surfaces formed through this technique, for Si-H free energies of formation, ΔGH, corresponding to a reaction mechanism including the elimination of two H atoms and the formation of a C=C double bond in either unreacted alkyl Grignard groups or tetrahydrofuran solvent.
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U2 - 10.1021/jp060640+
DO - 10.1021/jp060640+
M3 - Article
VL - 110
SP - 14842
EP - 14848
JO - Journal of Physical Chemistry B
JF - Journal of Physical Chemistry B
SN - 1520-6106
IS - 30
ER -