Kinetics Database Logo

Kinetics Database Resources

Simple Reaction Search

Search Reaction Database

Search Bibliographic Database

Set Unit Preferences

Feedback

Rate Our Products and Services

Help


Other Databases

NIST Standard Reference Data Program

NIST Chemistry Web Book

NDRL-NIST Solution Kinetics Database

NIST Computational Chemistry Comparison and Benchmark Database

The NIST Reference on Constants, Units, and Uncertainty

More...


Administrative Links

NIST home page

MML home page

Chemical Sciences Division

  NIST Logo Home
©NIST, 2013
Accessibility information
Author(s):   Zhang, Q.; Zhang, D.; Wang, S.; Gu, Y.
Title:   Ab Initio and Kinetic Calculations for the Reactions of H with (CH3)(4-n)GeHn (n=1,2,3,4)
Journal:   J. Phys. Chem. A
Volume:   106
Page(s):   122 - 129
Year:   2002
Reference type:   Journal article
Squib:   2002ZHA/ZHA122-129

Reaction:   CH3GeH3 + H2 + GeH3CH2*
Reaction order:   2
Rate expression:   no rate data available
Category:  Theory
Data type:   Ab initio
Comments:   Ab initio transition states for the abstraction reaction were calculated using MP2/6-31G(d) optimized geometries and frequencies and using energies from G2MP2 calculations. It was found that calculated barriers and heats of reactions were relatively insensitive to basis set, while the energetics were sensitive to the degree of electron correlation. MP2 energies were found to be inadequate, while value calculated using QCISD(T) energies were in good agreement with the experimental heat of reaction for GeH4 + H = GeH3 + H2. The transition states were used with Truhlars Polyrate program and including a CVT/SCT (canonical variational transition state theory / small curvature tunneling) correction. The transition states for the Ge-H+H abstraction reactions from GeH4 through GeH(CH3)3 were essentially collinear (Ge-H-H bond angle 177-180o).

Calculated barriers for the abstractions were relatively insensitive to methyl substitution, with the computed barrier heights being 2-3 kcal/mol. This compares to computed barriers of 10-13 kcal/mol for abstraction of C-H from the methyl groups (thus the latter being a minor channel).

Energies relatively independent of basis set 6-311G(d,p) to 6-311++G(3df,3pd)but MP2 give barriers about 3 kcal/mol higher (6 vs. 3 kcal/mol) and poor agreement between calculated and experimental heat of reaction.

No rate expression determined. Calculated barrier of 12.5 kcal/mol.

View full bibliographic record.