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    Analysis of the xylenol isomers by femtosecond laser time of flight mass spectrometry
    (CANADIAN SCIENCE PUBLISHING, NRC RESEARCH PRESS, 2018) Kepceoglu, A.; Koklu, N.; Gundogdu, Y.; Dereli, O.; Kilic, H. S.
    Xylenol is a phenolic chemical substance having two methyl groups and one hydroxyl group attached to a benzene ring and has six isomers. 2,4-xylenol is the only isomer of the xylenol molecule that is in the liquid phase while the remaining isomers are all in crystal form at room temperature. In the scope of this study, we have experimentally investigated ionization and dissociation properties of xylenol isomers. All experiments were carried out by using a time of flight mass spectrometry (TOF-MS) system coupled with a femtosecond laser system. The laser pulse power-dependent multiphoton ionization of xylenol isomers was investigated by using IR (800 nm) femtosecond laser pulses having a pulse width of similar to 90 fs in duration and laser intensities changing from 2.6 x 10(13) to 2.6 x 10(14) W/cm(2). Theoretically, molecular orbitals (LUMO+1, LUMO, HOMO, HOMO-1), vertical and adiabatic ionization energies were calculated using density functional theory (DFT) with B3LYP functional and 6-311++G(d,p) basis set by following geometry optimization and performing conformational analysis.
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    Molecular Structure and the EPR Calculation of the Gas Phase Succinonitrile Molecule
    (AMER INST PHYSICS, 2017) Kepceoglu, A.; Kilic, H. S.; Dereli, O.
    Succinonitrile (Le. butanedinitrile) is a colorless nitrile compound that can be used in the gel polymer batteries as a solid-state solvent electrolytes and has a plastic crystal structure. Prior to the molecular structure calculation of the succinonitrile molecule, the conformer analysis were calculated by using semi empirical method PM3 core type Hamiltonian and eight different contbrmer structures were determined. Molecular structure with energy related properties of these confomiers having the lowest energy was calculated by using DFT (B3LYP) methods with 6-311++G(4) basis set. Possible radicals, can be formed experimentally. were modeled in this study. EPR parameters of these model radicals were calculated and then compared with that obtained experimentally.