Papers by Keyword: Excited State

Abstract: Our theoretical study aims to analyze the Way of Obtain C₄H₆O⁺ macro ion by C₇H₁₂O⁺ Excited State and gives out a result with proved and directed significance for the corresponding experiments. Using the CIS(Configuration Interaction with Single Substitute) method, we calculated the frequency of cycloheptanone ion excited state. It is the parent ion 1C-7C, 4C-5C fracture, generates C₄H₆O⁺ pieces. It mainly through the fifth excited state occur the dissociation process.

Abstract: Abstract：Our theoretical study aims to analyze ionization and dissociation mechanism of cyclopentanone in the excited states and gives out a result with proved and directed significance for the corresponding experiments. Using the CIS（Configuration Interaction with Single Substitute） method, and 6-31+G (d, p) basis set, we calculated the frequency of excited state of cyclopentanone ion molecule. We have investigated the different vibration patterns of C-C bond and C-H bond under different excited states with imaginary frequency. Five dissociation channels have been obtained. Generally, the possible dissociation fragments in the excited state。

Abstract: We issue the theoretical calculation of C7H12O+ excited state, the corresponding vibration mode is given by the Gaussian03 calculation; In the analysis of vibration mode, it gives the possibility of C7H12O+ dissociation into fragments and the corresponding fragment analysis. In order to obtain relevant data of the fragments dissociation mechanism, we take the way analysis of C6H10O+ ion fragmentation as an example, then the bridge of experiment and theoretical calculations will provide a reference basis.

Abstract: The electronic excitations and electron absorption spectra of polychlorinated dibenzo-p-dioxins (PCDDs) were investigated by the time-dependent density functional theory (/DFT). The main spectral features were interpreted on the basis of the electronic structure of PCDDs by fully considering the possible interference of coexist organic molecules for the electron spectra. With the numbers of benzene rings in aromatic molecules increasing, the excitation energies decrease. The excitation energies of the compounds with three or four benzene rings (phenanthrene or fluoranthene) fall into the electronic transition regions of PCDDs. Therefore these compounds were not possible differentiate from the electron spectra of PCDDs. Furthermore, with the amounts of benzene rings extending to surpass three and four, the energies decease continuously and run beyond of the transition energy ranges of PCDDs. Thus the electron excitation energies of those aromatic molecules with three or four benzene rings were in the range of PCDDs, acting as the possible interferential substances for the detecting of PCDDs.

Abstract: The charge transfer and structural distortions that occurred in the complex CpRh(CO)₂ upon excitation with an light irradiation were studied by density functional theory (DFT). The calculations showed that the electrons transferred from Cp to CO ligands with the transition of CpRh(CO)₂ from ground state to the first excited state. Accompanying with this transfer process, CpM(CO)₂ became distorted and the linear bond of M-CO became bent upon excitation. The second excitation is the strongest excitation which is identified to be metal to ligand CO charge transfer (MLCT) excitations. We also found the lowest excited state has little effect for the M-CO bond photoactivation while the photodissociation of CO from CpM(CO)₂ can be achieved in the second excited state.

Abstract: The excited states of methyl methacrylate(MMA) were calculated by CIS method, MMA molecules on the ground and excited states of molecular structures were optimized. The HOMO and LUMO molecular orbitals of MMA molecule are given in the ground state and excited state . The results show that: MMA is excited, the molecular orbital from 27 → 28, the excitation energy is 1.4310eV, Carbon-carbon（C=C）double bonds break.

Abstract: We apply the Lee-Low-Pines-Huybrechts variational method to study the properties of the two and three dimensional bipolaron in a quantum dot. The ground-state (GS) and two types of excited-state energies of the Fröhlich bipolaron for the whole range of electron-phonon coupling constants can be obtained. Compared with the Franck-Condon excited state, the first relaxed excited state has a lower energy. Effects of quantum dot confinement on the excitation energies of the bipolaron are given.