https://doi.org/10.1140/epjd/e2008-00136-9
Thermodynamic properties of the most stable gaseous small silicon-carbon clusters in their ground states*
1
School of Natural and Applied Sciences, Northwestern Polytechnical University, Xi'an 710072, Shaanxi, P.R. China
2
National Key Laboratory of Thermostructure Composite Materials, Northwestern Polytechnical University, Xi'an 710072, Shaanxi, P.R. China
Corresponding author: a sukehe@nwpu.edu.cn
Received:
14
March
2008
Revised:
11
June
2008
Published online:
11
July
2008
The most stable structures of gaseous SimCn
(
) clusters in their ground electronic states are
determined with the high level electronic correlation method
QCISD(T)/g3large. Thermodynamic properties on heat capacity
(
, entropy (
, Gibbs energy function
(
) and enthalpy function
(
) are predicted with standard statistical
thermodynamics using the structure parameters and vibrational frequencies
obtained with B3PW91/6-31G(d) method combined with the electronic excitation
energies determined with time dependent density functional (TD DFT) method
at B3PW91/6-31G(d) level. The electronic energies are calculated with the
accurate model chemistry method at G3(QCI) level of theory and the 
(0 K), 
(298.15 K) and 
(298.15 K) values are predicted. The heat capacities
as a function of temperature within 298.15–2000 K are
fitted into analytical equations. The thermodynamic functions at higher
temperatures are determined classically by using these equations. Most of
the results obtained in this work are consistent with the available
experiments.
PACS: 33.15.-e – Properties of molecules / 82.60.-s – Chemical thermodynamics / 36.40.-c – Atomic and molecular clusters
© EDP Sciences, Società Italiana di Fisica, Springer-Verlag, 2008
