Abstract
In this work the dielectric function of the dense semiclassical collisionless plasmas was investigated on the basis of the interaction potential which takes into account the effects of diffraction in a wide range of temperatures and densities. The dielectric function was analytically and numerically investigated in approximation of high frequencies. We obtained the expression for the real part of the dielectric function for collisionless plasma in high – frequency limit within asymptotic approximation. All obtained results are in a good agreement. Taking into account of the diffraction effect in a wide region of temperature and densities can lead to perceptible change in the dielectric function.