Dirac-Fock-Breit-Gaunt calculations for tungsten hexacarbonyl W(CO){sub 6}

Journal Article · Sat May 21 04:00:00 EDT 2016 · Journal of Chemical Physics

DOI:https://doi.org/10.1063/1.4948809· OSTI ID:22658010

The first all-electron fully relativistic Dirac-Fock-Breit-Gaunt (DFBG), Dirac–Fock (DF), and nonrelativistic (NR) Hartree-Fock (HF) calculations are reported for octahedral (O{sub h}) tungsten hexacarbonyl W(CO){sub 6}. Our DF and NR HF calculations predict atomization energy of 73.76 and 70.33 eV, respectively. The relativistic contribution of ∼3.4 eV to the atomization energy of W(CO){sub 6} is fairly significant. The DF and NR energy for the reaction W + 6CO → W(CO){sub 6} is calculated as −7.90 and −8.86 eV, respectively. The mean bond energy predicted by our NR and DF calculations is 142.5 kJ/mol and 177.5 kJ/mol, respectively, and our predicted DF mean bond energy is in excellent agreement with the experimental value of 179 kJ/mol quoted in the literature. The relativistic effects contribute ∼35 kJ/mol to the mean bond energy and the calculated BSSE is 1.6 kcal/mol, which indicates that the triple zeta basis set used here is fairly good. The mean bond energy and the atomization energy calculated in our DFBG SCF calculations, which include variationally both the relativistic and magnetic Breit effects, is 157.4 kJ/mol and 68.84 eV, respectively. The magnetic Breit effects lead to a decrease of ∼20 kJ/mol and ∼4.9 eV for the mean bond energy and atomization energy, respectively, for W(CO){sub 6}. Our calculated magnetic Breit interaction energy of −9.79 eV for the energy of reaction (ΔE) for W + 6CO → W(CO){sub 6} is lower by ∼1.90 eV as compared to the corresponding DF value (ΔE) and contributes significantly to the ΔE. A detailed discussion is presented of electronic structure, bonding, and molecular energy levels at various levels of theory for W(CO){sub 6}.

• OSTI ID: 22658010
• Journal Information: Journal of Chemical Physics, Journal Name: Journal of Chemical Physics Journal Issue: 19 Vol. 144; ISSN JCPSA6; ISSN 0021-9606
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
ATOMIZATION
BINDING ENERGY
BONDING
CARBON MONOXIDE
CARBONYLS
ELECTRONIC STRUCTURE
ENERGY LEVELS
HARTREE-FOCK METHOD
RELATIVISTIC RANGE
TUNGSTEN