Diradical and Ionic Characters of Open-Shell Singlet Molecular Systems

Masayoshi Nakano, Kotaro Fukuda, Soichi Ito, Hiroshi Matsui, Takanori Nagami, Shota Takamuku, Yasutaka Kitagawa, Benoît Champagne

Résultats de recherche: Contribution à un journal/une revueArticle

Résumé

The diradical and ionic natures of open-shell singlet systems have been investigated using new definitions of the diradical and ionic characters as well as of their densities within the valence configuration interaction (VCI) model with two electrons in two active orbitals. The two-site symmetric and asymmetric diradical models are examined by using these diradical/ionic characters. For realistic compounds, we investigate a diradicaloid diphenalenyl and a rectangular graphene nanoflake in the presence of an external static electric field, as well as π-stacked phenalenyl-derivative dimers with varying the intermonomer distance, where the central carbon atoms in the phenalenyl rings are substituted by boron (B) and nitrogen (N) atoms, respectively. It is found that the increase of charge asymmetricity induced by the static electric field decreases the diradical character and finally induces an ionic character in the ground state, while the first excited state is changed from pure ionic to diradical-dominant as the field amplitude increases. On the other hand, when increasing the intermonomer distance, the B/N substitution in the phenalenyl dimer changes the electronic state from open-shell singlet with small diradical character to closed-shell with large ionic character. These results indicate that the application of a static electric field to diradicaloids and the asymmetric substitution of a pancake bonded π-dimer combined with the variation of intermonomer distance could tune the diradical/ionic characters and therefore control the nonlinear optical responses.
langueAnglais
Pages861-873
Nombre de pages13
journalJournal of Physical Chemistry A
Volume121
Numéro4
Les DOIs
étatPublié - 2017

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Dimers
dimers
Electric fields
electric fields
Substitution reactions
substitutes
Atoms
Boron
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Electronic states
Excited states
Graphene
Ground state
configuration interaction
atoms
graphene
boron
Nitrogen
Carbon
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    Nakano, Masayoshi ; Fukuda, Kotaro ; Ito, Soichi ; Matsui, Hiroshi ; Nagami, Takanori ; Takamuku, Shota ; Kitagawa, Yasutaka ; Champagne, Benoît. / Diradical and Ionic Characters of Open-Shell Singlet Molecular Systems. Dans: Journal of Physical Chemistry A. 2017 ; Vol 121, Numéro 4. p. 861-873
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    title = "Diradical and Ionic Characters of Open-Shell Singlet Molecular Systems",
    abstract = "The diradical and ionic natures of open-shell singlet systems have been investigated using new definitions of the diradical and ionic characters as well as of their densities within the valence configuration interaction (VCI) model with two electrons in two active orbitals. The two-site symmetric and asymmetric diradical models are examined by using these diradical/ionic characters. For realistic compounds, we investigate a diradicaloid diphenalenyl and a rectangular graphene nanoflake in the presence of an external static electric field, as well as π-stacked phenalenyl-derivative dimers with varying the intermonomer distance, where the central carbon atoms in the phenalenyl rings are substituted by boron (B) and nitrogen (N) atoms, respectively. It is found that the increase of charge asymmetricity induced by the static electric field decreases the diradical character and finally induces an ionic character in the ground state, while the first excited state is changed from pure ionic to diradical-dominant as the field amplitude increases. On the other hand, when increasing the intermonomer distance, the B/N substitution in the phenalenyl dimer changes the electronic state from open-shell singlet with small diradical character to closed-shell with large ionic character. These results indicate that the application of a static electric field to diradicaloids and the asymmetric substitution of a pancake bonded π-dimer combined with the variation of intermonomer distance could tune the diradical/ionic characters and therefore control the nonlinear optical responses.",
    keywords = "open-shell molecular systems, Quantum chemistry",
    author = "Masayoshi Nakano and Kotaro Fukuda and Soichi Ito and Hiroshi Matsui and Takanori Nagami and Shota Takamuku and Yasutaka Kitagawa and Beno{\^i}t Champagne",
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    pages = "861--873",
    journal = "Journal of Physical Chemistry A",
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    Diradical and Ionic Characters of Open-Shell Singlet Molecular Systems. / Nakano, Masayoshi; Fukuda, Kotaro; Ito, Soichi; Matsui, Hiroshi; Nagami, Takanori; Takamuku, Shota; Kitagawa, Yasutaka; Champagne, Benoît.

    Dans: Journal of Physical Chemistry A, Vol 121, Numéro 4, 2017, p. 861-873.

    Résultats de recherche: Contribution à un journal/une revueArticle

    TY - JOUR

    T1 - Diradical and Ionic Characters of Open-Shell Singlet Molecular Systems

    AU - Nakano,Masayoshi

    AU - Fukuda,Kotaro

    AU - Ito,Soichi

    AU - Matsui,Hiroshi

    AU - Nagami,Takanori

    AU - Takamuku,Shota

    AU - Kitagawa,Yasutaka

    AU - Champagne,Benoît

    N1 - PMID: 28040897

    PY - 2017

    Y1 - 2017

    N2 - The diradical and ionic natures of open-shell singlet systems have been investigated using new definitions of the diradical and ionic characters as well as of their densities within the valence configuration interaction (VCI) model with two electrons in two active orbitals. The two-site symmetric and asymmetric diradical models are examined by using these diradical/ionic characters. For realistic compounds, we investigate a diradicaloid diphenalenyl and a rectangular graphene nanoflake in the presence of an external static electric field, as well as π-stacked phenalenyl-derivative dimers with varying the intermonomer distance, where the central carbon atoms in the phenalenyl rings are substituted by boron (B) and nitrogen (N) atoms, respectively. It is found that the increase of charge asymmetricity induced by the static electric field decreases the diradical character and finally induces an ionic character in the ground state, while the first excited state is changed from pure ionic to diradical-dominant as the field amplitude increases. On the other hand, when increasing the intermonomer distance, the B/N substitution in the phenalenyl dimer changes the electronic state from open-shell singlet with small diradical character to closed-shell with large ionic character. These results indicate that the application of a static electric field to diradicaloids and the asymmetric substitution of a pancake bonded π-dimer combined with the variation of intermonomer distance could tune the diradical/ionic characters and therefore control the nonlinear optical responses.

    AB - The diradical and ionic natures of open-shell singlet systems have been investigated using new definitions of the diradical and ionic characters as well as of their densities within the valence configuration interaction (VCI) model with two electrons in two active orbitals. The two-site symmetric and asymmetric diradical models are examined by using these diradical/ionic characters. For realistic compounds, we investigate a diradicaloid diphenalenyl and a rectangular graphene nanoflake in the presence of an external static electric field, as well as π-stacked phenalenyl-derivative dimers with varying the intermonomer distance, where the central carbon atoms in the phenalenyl rings are substituted by boron (B) and nitrogen (N) atoms, respectively. It is found that the increase of charge asymmetricity induced by the static electric field decreases the diradical character and finally induces an ionic character in the ground state, while the first excited state is changed from pure ionic to diradical-dominant as the field amplitude increases. On the other hand, when increasing the intermonomer distance, the B/N substitution in the phenalenyl dimer changes the electronic state from open-shell singlet with small diradical character to closed-shell with large ionic character. These results indicate that the application of a static electric field to diradicaloids and the asymmetric substitution of a pancake bonded π-dimer combined with the variation of intermonomer distance could tune the diradical/ionic characters and therefore control the nonlinear optical responses.

    KW - open-shell molecular systems

    KW - Quantum chemistry

    U2 - 10.1021/acs.jpca.6b11647

    DO - 10.1021/acs.jpca.6b11647

    M3 - Article

    VL - 121

    SP - 861

    EP - 873

    JO - Journal of Physical Chemistry A

    T2 - Journal of Physical Chemistry A

    JF - Journal of Physical Chemistry A

    SN - 1089-5639

    IS - 4

    ER -