Excitation of naphthalene by electron impact

McConkey, J W; Trajmar, S.; Man, Kin F.; Ratliff, J. M.

doi:10.1088/0953-4075/25/9/023

Cited by 23 publications

(36 citation statements)

References 37 publications

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“…The value is in accord with experiment (3.0 eV), and is used to define the TDF for spin-coupling interaction (eq ). We obtained a vertical excitation energy of 4.52 eV 1 L a singlet state (eq ) from MSDFT@PBE0, falling in the range of experimental observations (4.45 , and 4.7 eV) …”

Section: Resultsmentioning

confidence: 64%

“…43 We obtained a vertical excitation energy of 4.52 eV 1 L a singlet state (eq 10) from MSDFT@PBE0, falling in the range of experimental observations (4.45 106,107 and 4.7 eV). 108 For the diabatic coupling between the symmetry-allowed spin-adapted states E 14−15 TDF (eqs 14 and 15), we used the average of the two spin-coupling values determined with eq 9 106,107 because the transition energies are nearly degenerate for HOMO − 1 → LUMO (4.48 eV) and HOMO → LUMO + 1 (4.51 eV) single excitations. 68 This yields an energy for 1 L b of 4.14 eV in comparison with the experimental value of 3.97 EV.…”

Section: Resultsmentioning

confidence: 99%

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Block-Localized Excitation for Excimer Complex and Diabatic Coupling

Bao

Hettich

Shi

et al. 2020

J. Chem. Theory Comput.

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We describe a block-localized excitation (BLE) method to carry out constrained optimization of block-localized orbitals for constructing valence bond-like, diabatic excited configurations using multistate density functional theory (MSDFT). The method is an extension of the previous block-localized wave function method through a fragment-based ΔSCF approach to optimize excited determinants within a molecular complex. In BLE, both the number of electrons and the electronic spin of different fragments in a whole system can be constrained, whereas electrostatic, exchange, and polarization interactions among different blocks can be fully taken into account of. To avoid optimization collapse to unwanted states, a ΔSCF projection scheme and a maximum overlap of wave function approach have been presented. The method is illustrated by the excimer complex of two naphthalene molecules. With a minimum of eight spin-adapted configurational state functions, it was found that the inversion of L a − and L b − states near the optimal structure of the excimer complex is correctly produced, which is in quantitative agreement with DMRG-CASPT2 calculations and experiments. Trends in the computed transfer integrals associated with excited-state energy transfer both in the singlet and triplet states are discussed. The results suggest that MSDFT may be used as an efficient approach to treat intermolecular interactions in excited states with a minimal active space (MAS) for interpretation of the results and for dynamic simulations, although the selection of a small active space is often system dependent.

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Section: Resultsmentioning

confidence: 64%

Section: Resultsmentioning

confidence: 99%

Block-Localized Excitation for Excimer Complex and Diabatic Coupling

Bao

Hettich

Shi

et al. 2020

J. Chem. Theory Comput.

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“…The photostability of this molecule has been extensively studied, indicating that the main dissociation channels at low photon energies involve the loss of a hydrogen atom or an acetylene molecule (C 2 H 2 ). − In terms of naphthalene excitation by electron impact, a systematic study on PAHs reports its ionization potential to be 8.2 eV . The electron impact ionization cross section has also been determined experimentally . In addition, the stability of naphthalene under high energy electron impact (1 keV) has been studied by means time-of-flight mass spectrometry, focusing on the C 2 H 2 -loss dissociation channel .…”

Section: Introductionmentioning

confidence: 99%

“…16 The electron impact ionization cross section has also been determined experimentally. 17 In addition, the stability of naphthalene under high energy electron impact (1 keV) has been studied by means time-of-flight mass spectrometry, focusing on the C 2 H 2 -loss dissociation channel. 18 As regards plasma processing of naphthalene, the literature is scarce.…”

Section: Introductionmentioning

confidence: 99%

Ionic Species in a Naphthalene Plasma: Understanding Fragmentation Patterns and Growth of PAHs

Alliati

Donaghy

et al. 2019

J. Phys. Chem. A

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The role of polycyclic aromatic hydrocarbons (PAHs) in the interstellar medium (ISM) is a key question in astrophysics. Moreover, our limited understanding of the plasma-driven processes of PAHs in the ISM motivates the present study on naphthalene as a model compound. In this work, a mass spectrometric characterization of the positive and negative ionic species in a naphthalene plasma was carried out. According to our findings, the main naphthalene dissociation channels upon electronic excitation proceed through hydrogen or acetylene loss. In addition, we report experimental evidence of the hydrogen abstraction-acetylene addition mechanism taking place under plasma conditions, which contributes to our understanding of the growth of PAHs. Regarding negative ions, species belonging to the astrochemically relevant family of polyynyl anions were detected, i.e., C 4 H − and C 6 H − . We postulate that the latter could be formed in a "top-down" chemistry as fragments of PAHs. Finally, our results show that negative ions add to neutral naphthalene molecules yielding larger anions, which suggests that negatively charged species may also play a role in the growth of PAHs.

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“…The transition energies at the superdimer structures, ranges from 4.99 to 5.16 eV, is slightly higher than the experimental value. 118,119 There is no BSSE by using BLW method because of separated basis sets. 45 Therefore, no BSSE is in the binding energies by using MSDFT calculation with same partition as monomers.…”

Section: A B a B I Fmentioning

confidence: 99%

Diabatic States,Couplings and Potential Energy Surfaces through the Block Localized Excitation Method

Bao,

Shi,

Gao

2020

Preprint

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We propose a new block localized excitation (BLE) method to directly construct diabatic excited states without the need to first compute the adiabatic states. The new method is capable to keep any electrons, spins, and excitations localized in any divided blocks of intermolecular and intramolecular systems. At the same time, the electrostatic, exchange, and polarization interactions between different blocks can be fully taken account of. To achieve this, a new ∆SCF project method and the maximum 1 wavefunction overlap method are employed to obtain localized excited states with orbitals relaxation, and the coupling between them are obtained using approaches similar to the multistate DFT (MSDFT) method. Numerical results show that the new BLE method is accurate in calculating the electronic couplings of the singlet excitation energy transfer (SEET) and triplet energy excitation transfer (TEET) processes, as well as the excited-state intermolecular potential energy surface.

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Excitation of naphthalene by electron impact

Cited by 23 publications

References 37 publications

Block-Localized Excitation for Excimer Complex and Diabatic Coupling

Block-Localized Excitation for Excimer Complex and Diabatic Coupling

Ionic Species in a Naphthalene Plasma: Understanding Fragmentation Patterns and Growth of PAHs

Diabatic States,Couplings and Potential Energy Surfaces through the Block Localized Excitation Method

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