Vibrational spectroscopic (FT-IR and FT-Raman) studies, HOMO–LUMO, NBO analysis and MEP of 6-methyl-1-({[(2E)-2-methyl-3-phenyl-prop- 2-en-1-yl]oxy}methyl)-1,2,3,4-tetra-hydroquinazoline-2,4-dione, a potential chemotherapeutic agent, using density functional methods Sr.S.H.Roseline Sebastian a,b , Abdul-Malek S. Al-Tamimi c , Nasser R. El-Brollosy d , Ali A. El-Emam d , C. Yohannan Panicker e,⇑ , Christian Van Alsenoy f a Department of Physics, Karpagam University, Eachanari, Coimbatore, Tamil Nadu, India b Christhu Jyothi Public School, Rajakkad, Idukki, Kerala, India c Department of Pharmaceutical Chemistry, College of Pharmacy, Salman Bin Abdulaziz University, Alkharj 11942, Saudi Arabia d Department of Pharmaceutical Chemistry, College of Pharmacy, King Saud University, Riyadh 11451, Saudi Arabia e Department of Physics, TKM College of Arts and Science, Kollam, Kerala, India f Department of Chemistry, University of Antwerp, B2610 Antwerp, Belgium highlights  IR, Raman spectra and NBO analysis were reported.  The wavenumbers are calculated theoretically using Gaussian09 software.  The wavenumbers are assigned using PED analysis.  The geometrical parameters are in agreement with XRD data. graphical abstract article info Article history: Received 10 April 2014 Received in revised form 19 May 2014 Accepted 3 June 2014 Available online 25 June 2014 Keywords: Quinazoline FTIR FT-Raman Hyperpolarizability abstract 6-Methyl-1-({[(2E)-2-methyl-3-phenyl-prop-2-en-1-yl]oxy}methyl)-1,2,3,4-tetra-hydroquinazoline-2,4- dione was prepared via treatment of silylated 6-methylquinazoline-2,4-dione with bis-[(E)-2-methyl-3- phenylallyloxy]methane. FT-IR and FT-Raman spectra were recorded and analyzed. The vibrational wavenumbers were computed using DFT methods and are assigned with the help of potential energy distribution method. The first hyperpolarizability, infrared intensities and Raman activities also reported. The geometrical parameters of the title compound obtained from XRD studies are in agreement with the calculated (B3LYP) values. The stability of the molecule arising from hyper-conjugative interac- tion and charge delocalization has been analyzed using NBO analysis. The HOMO and LUMO analysis are used to determine the charge transfer within the molecule. MEP was performed by the B3LYP method and from the MEP it is evident that the negative charge covers the C@O group and the positive region is over the phenyl ring and NH group. Ó 2014 Elsevier B.V. All rights reserved. http://dx.doi.org/10.1016/j.saa.2014.06.039 1386-1425/Ó 2014 Elsevier B.V. All rights reserved. ⇑ Corresponding author. Tel.: +91 9895370968. E-mail address: cyphyp@rediffmail.com (C. Yohannan Panicker). Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy 134 (2015) 316–325 Contents lists available at ScienceDirect Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy journal homepage: www.elsevier.com/locate/saa