In this paper we present experimental and simulated data of the second harmonic response for arbitrarily oriented linear input polarization and output polarization on Si(111) surfaces. In contrast to other nonlinear optical ellipsometry experiments (e.g. nonlinear optical null ellipsometry) we azimuthally rotate the sample for additional analysis of the crystal structure. In our study, we used the simplified bond hyperpolarizability model (SBHM) to simulate the observed angular shifts of the nonlinear peaks and the change of symmetry features related to a modification of the beam polarizations. Our findings help to identify the corresponding interface dipolar and bulk quadrupolar SHG sources. (C) 2016 Elsevier B.V. All rights reserved.