The Fourier transform infrared (FTIR) spectrum of 2-hydroxy-2-methyl-1-phenylpropan-1-one has been measured in the region 4000–700？ . The most stable conformation of title molecule was found after a careful potential energy surfaces study. The molecular geometry, vibrational frequencies, and infrared intensities have been calculated by using ab initio HF and density functional theory calculation B3LYP with 6-311+ basis set. Scaled frequencies and potential energy distribution were calculated for band assignment. We found an excellent agreement between the experimental and the simulated spectra. Energy gap between HOMO and LUMO explains the eventual charge transfer interactions taking place within the molecule. 1. Introduction The radiation curing industry is one of the most rapidly developing fields in the entire coating industry. The low toxicity, cheapness, speed, control, and ease of formulation and operation are some of the main advantages of this growing technology. UV and/or visible light radiation is used to induce photochemical polymerization or cross-linking of a monomer, oligomer, or prepolymer formulation containing a certain type of unsaturation, such as an acrylic group, and an appropriate initiator [1, 2]. Among the large group of known photoinitiator structures, hydroxyalkylphenones, such as 2-hydroxy-2-methyl-1-phenylpropan-1-one (Figure 1), have gained much interest due to their high reactivity and universal applicability [3, 4]. Figure 1: The optimized geometrical structure with atoms numbering of 2-hydroxy-2-methyl-1-phenylpropan-1-one. Despite the high practical value of title molecule, its physicochemical properties have been relatively little looked into [8–12]. To our best knowledge no structural data and detailed interpretation of the vibrational spectra of the title molecule are presented in the literature. This prompted us to look into the vibrational spectroscopy of the title molecule more carefully. 2. Experimental 2-Hydroxy-2-methyl-1-phenylpropan-1-one (purity 97%) was purchased from Sigma-Aldrich and used as such without further purification. The infrared spectra of liquid films placed between KBr pellets were recorded within 4000–700？cm？1 range with a Perkin Elmer FTIR System-2000 model. 3. Computational Potential energy curves were obtained by calculating the variation of total energy of title molecule with dihedral angles. For this purpose the calculations were performed with B3LYP functional and 6-311+G** basis set. The dihedral angles were varied from 0° to 360° with an interval of 10°. All DFT calculations were
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