Results in Physics 6 (2016) 1036–1043 Contents lists available at ScienceDirect Results in Physics journal homepage: www.journals.elsevier.com/results-in-physics Structure and electronic properties of substitutionally doped Cycloheptane molecule using DFT ⇑ Rajaa K. Mohammad, Rajaa A. Madlol, Nibras M. Umran, Fadhil I. Sharrad Department of Physics, College of Science, University of Kerbala, 56001 Karbala, Iraq article info abstract Article history: A density functional theory (DFT) has been carried out of the calculation molecular structure of Received 7 October 2016 Cycloheptane molecule (C7H14) with Gaussian 09 and Gaussian view 5.08 programs. The effects of the Received in revised form 10 November 2016 substitution Silicon atom in place of the Carbon atom and substituting the one Hydrogen atom by one Accepted 18 November 2016 hydroxyl (OH) were performed using DFT at B3LYP level with CC-PVDZ basis set. The optimized structure, Available online 22 November 2016 ionization potential, electron affinity, energy gap, electronegativity, total energies, force constant, reduces mass, Raman spectral, electrostatic potential surface and electron density surface were calculated. The Keywords: results showed decrease in energy gaps, increases in the electron affinity, and discusses the effect of DFT the substitution for all properties. Cycloheptane Ó Ionization potential 2016 The Author. Published by Elsevier B.V. This is an open access article under the CC BY license (http:// Electron affinity creativecommons.org/licenses/by/4.0/). Energy gap Raman spectrum Introduction activities and infrared intensities for tetraoxa [8] circulenes. The calculated quantum-chemical were in excellent agreement with Cycloheptane is an organic semiconductor with the molecular the experimental spectra [8]. The investigation of the effects of a 3 formula C7H14, and has density 0.8110 g/cm and molar mass variety of substitutes (H, NH2, NMe2, OCH3,CH3, Cl, Br, CN and À1 98.19 g.mol [1]. NO2) on the electronic and structural properties of 2,4-diamino- Aromatic compounds are important in industry and play roles 5-p-substituted-phenyl-6-ethyl-pyrimidines had been used den- in the biochemistry of all living things, whereas solar cells and sity functional theory (DFT) method at the level of B3LYP with 6- photovoltaic, organic light emitting diodes (OLEDs), thin film tran- 311G(d) basis set [9]. The complex heterogeneous nature of chars sistors [2,3]. Many studies had been done to calculate electronic had confounded the complete analysis of the Raman spectra of properties. FT-Raman, UV, FT-IR and NMR spectra were measured these materials [10]. In other studies, the cyclic conformational in the condensed state as well as compared with the experimental coordinates are essential for the variation of molecular ring con- data. It was done using DFT/B3LYP method with 6-311++G(d,p) as formers as the use of Cremer-Pople coordinates have explain for basis set of 2-(2-benzothiazolylthio)-ethanol [4]. Electronic prop- five- and six-membered rings. So useful for correlating, the physi- erties and infrared spectra of diamondoids were calculated using cal properties of macrocycles with their ring pucker and measuring DFT method [5]. The DFT method was used for the optimization the dynamic ring conformational behavior to varieties of canonical structure of the ground state and simulation of the Raman and states were given for cycloheptane and cyclooctane which had infrared spectra of trichloro cyclohexylsilane molecule [6]. The been previously experimentally analyzed [11]. Femtosecond basic parameters of design and fabrication of an organic solar cell Raman rotational coherence spectroscopy (RCS) detected by were HOMO and LUMO of organic compounds [7]. The DFT/ degenerate four-wave mixing is a background-free method that B3LYP method with the 6-31G (d) basis set using the symmetry allows to determine accurate rotational, vibration-rotation cou- constraints had been used to calculate the harmonic vibrational pling constants, and centrifugal distortion constants of cyclopen- frequencies, equilibrium molecular geometry, Raman scattering tane (C5H10). They are finding the lowest-frequency vibration in a pseudorotating ring deformation that interconverts 10 permuta- tionally distinct but energetically degenerate ‘‘twist” minima inter- spersed by 10 ‘‘bent” conformers. While the individual twist and ⇑ Corresponding author. bent structures are polar asymmetric tops, the pseudorotation is E-mail address: [email protected] (F.I. Sharrad). http://dx.doi.org/10.1016/j.rinp.2016.11.039 2211-3797/Ó 2016 The Author. Published by Elsevier B.V. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/). R.K. Mohammad et al. / Results in Physics 6 (2016) 1036–1043 1037 Fig. 1. The optimized structures of Cycloheptane (A), 7-monosilicon-Cycloheptane (B) and 7-monosilicon-7-hydroxyl-Cycloheptane (C) molecules using DFT method with CC-PVDZ basis set. Fig. 2. The density of state of (A) Cycloheptane, (B) 7-monosilicon-Cycloheptane and (C) 7-monosilicon-7-hydroxyl-Cycloheptane molecules using DFT method with CC-PVDZ basis set. 1038 R.K. Mohammad et al. / Results in Physics 6 (2016) 1036–1043 Table 1 The HOMO, LUMO, and Energy gap (Eg) in eV values units, while the total energy in a.u. unit. Molecules HOMO (eV) LUMO (eV) Eg (eV) Total energy (a.u.) Cycloheptane À8.1665 1.3744 9.5409 À275.1897 7-monosilicon-Cycloheptane À7.6966 1.0443 8.7409 À526.5910 7-monosilicon-7-hydroxyl-Cycloheptane À7.3461 0.9395 8.2857 À601.8635 12 12 Cycloheptane 7-monosilicon-Cycloheptane 10 10 8 8 6 6 4 4 2 2 0 0 0 50 100 150 Density of Tetrahedral Angles of Tetrahedral Density 0 50 100 150 Density of Tetrahedral Angles of Tetrahedral Density -2 -2 Tetrahedral Angle(degrees) Tetrahedral Angle(degrees) 7-monosilicon-7-hydroxyl- Cycloheptane 12 10 8 6 4 2 0 -2 0 50 100 150 Density of Tetrahedral of Angles Tetrahedral Density Tetrahedral Angle(degrees) Fig. 3. The density of tetrahedral angles for Cycloheptane, 7-monosilicon-Cycloheptane and 7-monosilicon-7-hydroxyl-Cycloheptane molecules using DFT method with CC- PVDZ basis set. fast on the time scale of external rotation, rendering cyclopentane Computational approach a fluxionally nonpolar symmetric top molecule [12]. In more details conformational analysis of cyclopentane and its derivatives All computational procedure was carried out using Gaussian were performed using DFT (xxb97xd/6-311+G (d, p)) level of the- 09 and Gaussian view 5.08 programs [14]. The optimization ory. The researchers found, the concept of a spherical conforma- structure of Cycloheptane, 7-monosilicon-Cycloheptane and tional and scape represents two concentric ring coordinates for 7-monosilicon–7-hydroxyl-Cycloheptane molecules with twisting and bending pathways in cyclopentane and its derivatives substitution Silicon and hydroxyl in positions of Hydrogen atom which helped fully explain their fluxional nature, confirmed by have been performed with B3LYP/CC-PVDZ level in the gas phase 1100–1600 cm1 region of their Raman spectra [13]. and DFT method. The energy of the highest occupied molecular In the present work, we have studied the optimized structure, orbital is EHOMO and the energy of the lowest unoccupied molecular ionization potential, electron affinity, energy gap, electronegativ- orbital is ELUMO. The energy gap computed using the following ity, total energies, force constant, reduces mass, Raman spectral, equation [15]: electrostatic potential surface and electron density surface using D ¼ LUMO À HOMO ð Þ DFT for Cycloheptane molecule (C7H14) with the effects of the sub- Egap E E 1 stitution Silicon atom in place of the Carbon atom and substituting the one Hydrogen atom by one hydroxyl (OH). Furthermore, we are Ionization potential (IP) and electron affinity (EA) can have been interest to study the properties of Cycloheptane because of the calculated using equations [16]. scarcity of research. The aromatic compounds are important in HOMO industry for multiple uses, such as in the biochemistry of all living IP ¼E ð2Þ things, whereas solar cells and photovoltaic, organic light emitting diodes (OLEDs), thin film transistors. EA ¼ELUMO ð3Þ R.K. Mohammad et al. / Results in Physics 6 (2016) 1036–1043 1039 Cycloheptane 7-monosilicon-Cycloheptane 6 4.5 4 5 3.5 4 3 2.5 3 2 2 1.5 1 1 0.5 0 0 Density of Dihdral Angles -200 -100-0.5 0 100 200 -200 -100-1 0 100 200 Density of Dihdrel Angles -1 Dihdral Angle(degrees) Dihedral Angle(degrees) 7-monosilicon-7-hydrxyl -Cycloheptane 3.5 3 2.5 2 1.5 1 0.5 0 -200Density of Dihdral Angeles -100 0 100 200 -0.5 Dihdral Angle(degrees) Fig. 4. The density of dihedral angles for Cycloheptane, 7-monosilicon-Cycloheptane and 7-monosilicon-7-hydroxyl-Cycloheptane molecules using DFT method with CC- PVDZ basis set. heptane molecules have been shown in Fig. 2. In doping case, the Table 2 The ionization potential (IP), electron affinity (EA) and electronegativity (X) values of electronic bands are continuous and the energy levels are increas- values in eV units. ing, while the energy gaps are decreasing for the substitution atom (also, see Table 1). The energy gap indicated to the activity of mole- Molecules IP (eV) EA (eV) X (eV) cule in computed results and the7-monosilecon-7-hydroxyl-Cyclo À Cycloheptane 8.1665 1.3744 3.3960 heptane molecule has small energy gap 8.2857 eV, small energy 7-monosilicon-Cycloheptane 7.6966 À1.0443 3.3261 7-monosilicon-7-hydroxyl-Cycloheptane 7.3461 À0.9396 3.2032 gap indicated to the activity of molecule, while Cycloheptane has high energy gap 9.540 eV. While, the electronegativity (X) can be calculated using the fol- Density of tetrahedral angles lowing equation [17]. X ¼1=2ðEHOMO þ ELUMOÞð4Þ The values of density of tetrahedral angles of Cycloheptane,7- monosilicon-Cycloheptane and 7-monosilicon-7-hydroxyl-Cyclo heptane molecules are shown in Fig.