In this present study, the molecular structure and spectroscopic properties of 4-(4-chlorophenyl)-4-hydroxypiperidine (44C4HP, C11H14ClNO) were characterized by FT-IR, FT-Raman and UV–vis spectroscopy. FT-IR and FT-Raman spectra in solid state were observed in the region 4000–400 cm1 and 4000–100 cm1, respectively. The spectroscopic properties were also investigated by the density functional theory (DFT) method. The geometry optimizations in gas phase and solvent media were performed by DFT methods with B3LYP using 6-311++G(d,p) basis set. The ultraviolet absorption spectrum of the studied compound which can be dissolved in water and ethanol was examined in the range of 190–400 nm. The geometry optimizations in solvent media were performed by time-dependent density functional theory (TD-DFT) methods with B3LYP using 6-311++G(d,p) basis set. The highest occupied molecular orbital (HOMO), the lowest unoccupied molecular orbital (LUMO) energies, and absorption wavelength were calculated by the TD-DFT method. In addition, molecular electrostatic potential (MEP) and thermodynamic properties were obtained in the range of 100–700 K.
