NORMAL COORDINATE ANALYSIS AND MNDO CALCULATIONS - ASSIGNMENT OF THE VIBRATIONAL-SPECTRUM OF ACRIDINE

A combination of normal coordinate analysis (based on a Urey-Bradley-Kekule force field) (UBFF) and modified neglect of diatomic overlap (MNDO) calculations were employed to determine a qualitative working assignment of the vibrational spectrum of acridine. This assignment was employed in resonance Raman studies of the chromophoric acridine-based anti-tumour drug amsacrine. The assignments emerge from the potential energy distribution (PED) calculations in the normal coordinate analysis and from the potential energy minima and optimized geometry in the MNDO calculations. The MNDO frequency parameters were calibrated using the carbon-hydrogen stretching modes.