ON THE CALCULATION OF THE TILT ANGLE OF SUBSTITUTED ALKANES WITH RESPECT TO THE AIR/WATER INTERFACE IN FRAMEWORK OF PM3 APPROXIMATION

Abstract

In the framework of quantum chemical semiempiric PM3 method the procedure for estimation of the geometric parameters of 2D unit cells of substituted alkane monolayers at the air/water interface is proposed. Its application is illustrated on the examples of four surfactant classes with different size of their hydrophilic parts. It was shown that inclination of surfactant molecules with respect to the interface is determined by orientation and volume of the hydrophilic parts of molecules and CH•••HC interactions realized between their hydrophobic chains.