About diverse behavior of the molecular electric properties upon spatial confinement

•The electric properties of spatially limited OCS and ClCCH molecules are analyzed.•The effect of orbital compression is modeled by the cylindrical harmonic potential.•Orbital compression leads to the polarity inversion of chloroacetylene.•A nonmonotonic changes of polarizability anisotropy are noted for confined molecules.•Spatial restriction causes a nonmonotonic behavior of OCS first hyperpolarizability.

We report on the influence of spatial restriction on the static electric properties of two π-electron molecules, namely carbonyl sulfide and chloroacetylene. A two-dimensional harmonic oscillator potential has been applied in order to mimic the effect of orbital compression. All components of the studied tensorial quantities were obtained using the finite-field method. Among others, the nonmonotonic changes of the first hyperpolarizability, observed for the spatially limited OCS molecule, are described for the first time in the literature. Moreover, it has been found that upon embedding in cylindrical confining potential behavior of dipole moment is different for each of the investigated molecular systems. In order to explain the obtained diverse trends, the Hirshfeld technique as well as the concept of hyperpolarizability density has been adopted.

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