Effects of delocalised π-electrons around the linear acenes ring (<i>n</i>= 1 to 7): an electronic properties through DFT and quantum chemical descriptors

Musa, A.; Saeed, M. A.; Shaari, A.; Sahnoun, Riadh; Lawal, Monsurat M.

doi:10.1080/00268976.2014.993734

Cited by 8 publications

(6 citation statements)

References 26 publications

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“…But it is observed that at B3LYP level of theory the energy gap for all basis sets used is about 2.456eV for both gas and methanol. This value is more in agreement to a reported experimental value of 2.63 (Musa et al, 2015). Thus, B3LYP calculations are more in agreement with the experimental value due to the inclusion of electron correlation than RHF.…”

Section: Homo-lumo Energy Gapsupporting

confidence: 90%

“…In February 2014, National Aeronautic and space Agency (NASA) announced a greatly upgraded database for tracking polycyclic aromatic hydrocarbons (PAHs), including Tetracene, in the universe (Hoover, 2014). The frontier orbital (LUMO and HOMO) energies of tetracene molecule have been invetigated and reported by (Peter et al, 2009 andMusa et al, 2015).…”

Section: Introductionmentioning

confidence: 94%

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Geometry optimization and vibrational frequencies of tetracene molecule in gas phase and in methanol based on Density Funtional Theory and Restricted Hartree-Fock

Gidado¹,

Maigari²,

Galadanci³

2017

Bayero J. Pure App. Sci.

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Tetracene is an organic semiconductor with chemical formula C 18 H 12 used in organic field effecttransistor (OFET) and organic light emitting diode (OLED). In this work, the molecular geometry (optimized bond lengths and bond angles), vibrational frequencies and intensities, HOMO-LUMO Energy gap and Atomic charge distribution of the Tetracene molecule in gas phase and in solution were calculated and reported. Restricted Hartree-Fock (RHF) and Density Functional Theory (DFT) with different basis sets were employed for the task. Windows version of Gaussian 03 software was used to perform all the calculations. The results obtained show that the bond length obtained using RHF has the lowest average value of 1.072Å and that obtained using DFT has the lowest average value of 1.085Å in gas phase. In Methanol, it is observed that at RHF level, the lowest average value was 1.075Å and at DFT level was 1.087Å. This shows that the values are a bit higher in methanol than in gas phase which implies that the bonds will be slightly stronger in gas phase than in methanol. The strongest bonds in tetracene molecule are those of C20-H28, C23-H29 and C24-H30 in both gas and methanol. The weakest bonds are those of C6-C12 and C6-C14.The bond angles were found to be so closed to 120 0 at both levels of theory for all basis sets used suggesting that the molecule is planar benzene in which the C atoms are hybridized. The calculated HOMO-LUMO energy gap shows that the molecule will be slightly more stable in chemical reaction in gas phase than in methanol. DFT values of the energy gap appeared to be closer to the reported experimental value of 2.6eV than those obtained by RHF. The atomic charges distribution was found to be very sensitive to the basis sets which presumably occur due to polarization. From the results obtained for vibrational frequencies, it shows that tetracene molecule would be more stable in gas phase that in methanol as a result of no imaginary frequency found in gas phase. This confirms the stability of the molecule as stated in the results of HOMO-LUMO energy gap. The calculated vibrational frequencies show that the most intense frequency was obtained to be 924.9862cm -1 at 146.7973KM/mole by RHF/3-21G in gas phase while at B3LYP/3-21G, it has the most intense frequency of about 474.1260cm -1 at 390.1077.2845MK/mole in methanol.

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Section: Homo-lumo Energy Gapsupporting

confidence: 90%

Section: Introductionmentioning

confidence: 94%

Geometry optimization and vibrational frequencies of tetracene molecule in gas phase and in methanol based on Density Funtional Theory and Restricted Hartree-Fock

Gidado¹,

Maigari²,

Galadanci³

2017

Bayero J. Pure App. Sci.

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“…Due to the promising potential applications of materials which contain π-conjugated systems − to be used as chemical sensors, organic semiconductors, in spintronics and nonlinear optics, a large number of studies on graphene and its model systems appeared recently in the literature. − The electronic properties of polyacenes (PACs, Scheme ) not only are very attractive for material science, − but also they can serve as a model system for studying the properties of ground and excited states of extended π systems ,− by means of theoretical methods.…”

Section: Introductionmentioning

confidence: 99%

Singlet L_a and L_b Bands for N-Acenes (N = 2–7): A CASSCF/CASPT2 Study

Bettanin

Ferrão

Pinheiro

et al. 2017

J. Chem. Theory Comput.

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In this work CASPT2 calculations of polyacenes (from naphthalene to heptacene) were performed to find a methodology suitable for calculations of the absorption spectra, in particular of the L (B state) and L (B state) bands, of more extended systems. The effect of the extension of the active space and of freezing σ orbitals was investigated. The MCSCF excitation energy of the B state is not sensitive to the size of the active space used. However, the CASPT2 results depend strongly on the amount of σ orbitals frozen reflecting the ionic character of the B state. On the other hand, the excitation energies of the B state are much more sensitive to the size of the active space used in the calculations reflecting its multiconfigurational character. We found a good agreement with experimental data for both bands by including 14 electrons in 14 π orbitals in the active space followed by the CASPT2(14,14) perturbation scheme in which both σ and π orbitals are included.

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“…To examine the validity of our DFT simulations on the electronic properties of aromatic molecular rings, we shall check them against the literature [35–39]. The green circles show the experimental E g for seven moieties (note: no measurement for dibenzocoronene, see the electronic supplementary material, table S1).…”

Section: Resultsmentioning

confidence: 99%

Energy gap and aromatic molecular rings

Ismael,

Al-Jobory

2024

R. Soc. Open Sci.

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The manuscript combines rational density functional theory simulations and experimental data to investigate the electrical properties of eight polycyclic aromatic hydrocarbons (PAHs). The optimized geometries reveal a preference for one-row, two-row and three-row ring distributions. Band structure plots demonstrate an inverse correlation between the number of aromatic rings and band gap size, with a specific order observed across the PAHs. Gas phase simulations support these findings, though differences in values are noted compared to the literature. Introducing a two-row ring distribution concept resolves discrepancies, particularly in azulene. The B3LYP function successfully bridges theoretical and experimental gaps, particularly in large PAHs. The manuscript highlights the potential for designing electronic devices based on different-sized PAHs, emphasizing a multi-ring distribution approach and opening new avenues for practical applications.

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Effects of delocalised π-electrons around the linear acenes ring (n= 1 to 7): an electronic properties through DFT and quantum chemical descriptors

Cited by 8 publications

References 26 publications

Geometry optimization and vibrational frequencies of tetracene molecule in gas phase and in methanol based on Density Funtional Theory and Restricted Hartree-Fock

Geometry optimization and vibrational frequencies of tetracene molecule in gas phase and in methanol based on Density Funtional Theory and Restricted Hartree-Fock

Singlet L_a and L_b Bands for N-Acenes (N = 2–7): A CASSCF/CASPT2 Study

Energy gap and aromatic molecular rings

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Effects of delocalised π-electrons around the linear acenes ring (n= 1 to 7): an electronic properties through DFT and quantum chemical descriptors

Cited by 8 publications

References 26 publications

Geometry optimization and vibrational frequencies of tetracene molecule in gas phase and in methanol based on Density Funtional Theory and Restricted Hartree-Fock

Geometry optimization and vibrational frequencies of tetracene molecule in gas phase and in methanol based on Density Funtional Theory and Restricted Hartree-Fock

Singlet La and Lb Bands for N-Acenes (N = 2–7): A CASSCF/CASPT2 Study

Energy gap and aromatic molecular rings

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Singlet L_a and L_b Bands for N-Acenes (N = 2–7): A CASSCF/CASPT2 Study