کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
5376050 1504312 2008 13 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Accurate ab initio computation of thermochemical data for C3Hx(x=0,…,4) species
موضوعات مرتبط
مهندسی و علوم پایه شیمی شیمی تئوریک و عملی
پیش نمایش صفحه اول مقاله
Accurate ab initio computation of thermochemical data for C3Hx(x=0,…,4) species
چکیده انگلیسی
We have computed the atomization energies of nineteen C3Hx molecules and radicals using explicitly-correlated coupled-cluster theory including corrections for core-core and core-valence correlation, scalar and spin-orbit relativistic effects, and anharmonic vibrational zero-point energies. Equilibrium geometries were obtained at the coupled-cluster level [CCSD(T) model] in a correlation-consistent polarized core-valence quadruple-zeta basis set, using a spin-restricted Hartree-Fock reference wave function, and including all electrons in the correlation treatment. Applied to a set of selected CHx and C2Hx systems, our approach yields highly accurate atomization energies with a mean absolute deviation of 1.4 kJ/mol and a maximum deviation of 4.2 kJ/mol (for dicarbon) from the Active Thermochemical Tables (ATcT) values. The explicitly-correlated coupled-cluster approach provides energies near the basis-set limit of the CCSD(T) model, which is the coupled-cluster model with single and double excitations (CCSD) augmented with a perturbative correction for triple excitations (T). To obtain even more accurate atomization energies than those presented here, it would be required to include full triple excitations (CCSDT) and corrections for excitations beyond triples, as for instance done in the CCSDT(Q) model, which includes a perturbative correction for quadruple excitations (Q).
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Chemical Physics - Volume 346, Issues 1–3, 4 May 2008, Pages 56-68
نویسندگان
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