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Luis Luis, Josep Maria
MartÃ, Josep Duran i Portas, Miquel AndrÃ©s, JosÃ© LuÃs 

The influence of the basis set size and the correlation energy in the static electrical properties of the CO molecule is assessed. In particular, we have studied both the nuclear relaxation and the vibrational contributions to the static molecular electrical properties, the vibrational Stark effect (VSE) and the vibrational intensity effect (VIE). From a mathematical point of view, when a static and uniform electric field is applied to a molecule, the energy of this system can be expressed in terms of a double power series with respect to the bond length and to the field strength. From the power series expansion of the potential energy, fielddependent expressions for the equilibrium geometry, for the potential energy and for the force constant are obtained. The nuclear relaxation and vibrational contributions to the molecular electrical properties are analyzed in terms of the derivatives of the electronic molecular properties. In general, the results presented show that accurate inclusion of the correlation energy and large basis sets are needed to calculate the molecular electrical properties and their derivatives with respect to either nuclear displacements or/and field strength. With respect to experimental data, the calculated power series coefficients are overestimated by the SCF, CISD, and QCISD methods. On the contrary, perturbation methods (MP2 and MP4) tend to underestimate them. In average and using the 6311 + G(3df) basis set and for the CO molecule, the nuclear relaxation and the vibrational contributions to the molecular electrical properties amount to 11.7%, 3.3%, and 69.7% of the purely electronic Î¼, Î±, and Î² values, respectively  
http://hdl.handle.net/2072/101687  
eng  
American Institute of Physics  
Tots els drets reservats  
Camps elÃ¨ctrics
Carboni  Propietats elÃ¨ctriques DinÃ mica molecular Energia Stark, Efecte de Carbon  Electric properties Electric fields Force and energy Molecular dynamics Stark effect 

Systematic study of the static electrical properties of the CO molecule: influence of the basis set size and correlation energy  
info:eurepo/semantics/article  
Recercat 