Vibrational analysis of 4, 4'-methylene diphenyl diisocyanate

Abstract

Vibrational Raman and FT-IR absorption spectra of 4,4'-methylene diphenyl diisocyanate (MDI) have been recorded. The ab initio and density functional theory calculations (B3LYP/cc-pVDZ) have been performed for the MDI geometric structure and force field. The fully optimized structure has been obtained using Quadratic Approximation gradient method and is proved by its Hessian. Vibrational spectra have been simulated; bands and lines in IR or Raman spectra of the MDI molecule have been identified and attributed.