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

A combination of normal coordinate analysis (based on a Urey-Bradley-K ekule force field) (UBFF) and modified neglect of diatomic overlap (MN DO) calculations were employed to determine a qualitative working assi gnment of the vibrational spectrum of acridine. This assignment was em ployed in resonance Raman studies of the chromophoric acridine-based a nti-tumour drug amsacrine. The assignments emerge from the potential e nergy distribution (PED) calculations in the normal coordinate analysi s and from the potential energy minima and optimized geometry in the M NDO calculations. The MNDO frequency parameters were calibrated using the carbon-hydrogen stretching modes.