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: Recherche - Revue par des pairsArticle

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
electric fields
Dimers
Electric fields
substitutes
atoms
Substitution reactions
Atoms
configuration interaction
graphene
boron
valence
nitrogen
orbitals
ground state
carbon
rings
electronics
excitation
electrons

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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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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.",
author = "Masayoshi Nakano and Kotaro Fukuda and Soichi Ito and Hiroshi Matsui and Takanori Nagami and Shota Takamuku and Yasutaka Kitagawa and Benoît Champagne",
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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: Recherche - Revue par des pairsArticle

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.

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DO - 10.1021/acs.jpca.6b11647

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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 -