Abstract

Coumarin is a natural compound found in many plants. It has been successfully employed in dye lasers, and since 1996 it’s potentiality in the development of a high efficiency dye sensitized solar cell is being investigated. In this work, the Fritz-Haber Institut ab initio Molecular Dynamic Simulation code, FHI-aims was used to investigate the convergence of the Self-Consistency Field Cycle, obtain the most stable ground state atomic coordinates, and to generate and analyze the vibrational modes of coumarin (α-Benzopyrone. The exchange-correlation interactions are treated by the Linear Density Approximation. The ground state total energy of the molecule was found to be – 13531.52 eV. The result of the vibrational modes analysis confirmed that the optimized geometry is indeed a local minimum and not a saddle point. A total of 51 vibrational modes are identified with highest IR absorption of 14.15 D2Å -2 at 1789.57 cm-1. An important finding of the Self-Consistency Field Cycle convergence shows an error in the FHI-aims user manual.