We have used high-resolution near-edge X-ray absorption fine structure spectroscopy to study the N 1s -> 1 pi* resonance of N-2 trapped below the surface of several compound semiconductors. The vibrational fine structure, observed from all samples under consideration, exhibits substantially larger lifetime linewidth Gamma than in isolated N-2. A clear correlation between Gamma and the lattice constant of the host matrix has been found, indicating that the broadening of vibrational levels is governed by a finite probability of the electron to escape from the pi* orbital into the matrix. (c) 2006 Published by Elsevier B.V.