Precise PPP molecular orbital calculations of excitation energies of polycyclic aromatic hydrocarbons. Part 6. Spectrochemical atomic softness parameter†

2001 ◽  
pp. 975-980 ◽  
Author(s):  
Kimihiro Hiruta ◽  
Sumio Tokita ◽  
Tatsuya Tachikawa ◽  
Fumio Noguchi ◽  
Kichisuke Nishimoto
Keyword(s):  
Polycyclic Aromatic Hydrocarbons ◽  
Molecular Orbital ◽  
Aromatic Hydrocarbons ◽  
Molecular Orbital Calculations ◽  
Excitation Energies ◽  
Polycyclic Aromatic ◽  
Softness Parameter

Precise PPP molecular orbital calculations of excitation energies of polycyclic aromatic hydrocarbons. Part 5

2000 ◽  
Vol 44 (2) ◽  
pp. 123-129 ◽  
Author(s):  
Kimihiro Hiruta ◽  
Sumio Tokita ◽  
Tatsuya Tachikawa ◽  
Kichisuke Nishimoto
Keyword(s):  
Polycyclic Aromatic Hydrocarbons ◽  
Molecular Orbital ◽  
Aromatic Hydrocarbons ◽  
Molecular Orbital Calculations ◽  
Excitation Energies ◽  
Polycyclic Aromatic

scholarly journals Molecular Design of Polycyclic Aromatic Hydrocarbons Based on Precise PPP Molecular Orbital Calculations.

1996 ◽  
Vol 9 (1) ◽  
pp. 73-78 ◽  
Author(s):  
KIMIHIRO HIRUTA ◽  
SUMIO TOKITA ◽  
YOSHIHIRO DAIKOKU ◽  
KICHISUKE NISHIMOTO
Keyword(s):  
Polycyclic Aromatic Hydrocarbons ◽  
Molecular Orbital ◽  
Aromatic Hydrocarbons ◽  
Molecular Design ◽  
Molecular Orbital Calculations ◽  
Polycyclic Aromatic

scholarly journals Exploitation of Baird Aromaticity and Clar’s Rule for Tuning the Triplet Energies of Polycyclic Aromatic Hydrocarbons

Chemistry ◽  
2021 ◽  
Vol 3 (2) ◽  
pp. 532-549
Author(s):  
Felix Plasser
Keyword(s):  
Polycyclic Aromatic Hydrocarbons ◽  
Excited States ◽  
Aromatic Hydrocarbons ◽  
Density Functional ◽  
Materials Science ◽  
Chemical Shifts ◽  
Qualitative Description ◽  
Triplet States ◽  
Excitation Energies ◽  
Polycyclic Aromatic

Polycyclic aromatic hydrocarbons (PAH) are a prominent substance class with a variety of applications in molecular materials science. Their electronic properties crucially depend on the bond topology in ways that are often highly non-intuitive. Here, we study, using density functional theory, the triplet states of four biphenylene-derived PAHs finding dramatically different triplet excitation energies for closely related isomeric structures. These differences are rationalised using a qualitative description of Clar sextets and Baird quartets, quantified in terms of nucleus independent chemical shifts, and represented graphically through a recently developed method for visualising chemical shielding tensors (VIST). The results are further interpreted in terms of a 2D rigid rotor model of aromaticity and through an analysis of the natural transition orbitals involved in the triplet excited states showing good consistency between the different viewpoints. We believe that this work constitutes an important step in consolidating these varying viewpoints of electronically excited states.

A TDDFT study of the lowest excitation energies of polycyclic aromatic hydrocarbons

2003 ◽  
Vol 292 (1) ◽  
pp. 11-21 ◽  
Author(s):  
Maja Parac ◽  
Stefan Grimme
Keyword(s):  
Polycyclic Aromatic Hydrocarbons ◽  
Aromatic Hydrocarbons ◽  
Excitation Energies ◽  
Polycyclic Aromatic

scholarly journals Exploitation of Baird Aromaticity and Clar's Rule for Tuning the Triplet Energies of Polycyclic Aromatic Hydrocarbons

2021 ◽  
Author(s):  
Felix Plasser
Keyword(s):  
Polycyclic Aromatic Hydrocarbons ◽  
Excited States ◽  
Aromatic Hydrocarbons ◽  
Density Functional ◽  
Materials Science ◽  
Chemical Shifts ◽  
Qualitative Description ◽  
Triplet States ◽  
Excitation Energies ◽  
Polycyclic Aromatic

Polycyclic aromatic hydrocarbons (PAH) are a prominent substance class with a variety of applications in molecular materials science. Their electronic properties crucially depend on the bond topology in ways that are often highly non-intuitive. Here, we study, using density functional theory, the triplet states of four PAHs based on the biphenylene motif finding dramatically different triplet excitation energies for closely related isomeric structures. These differences are rationalised using a qualitative description of Clar sextets and Baird quartets, quantified in terms of nucleus independent chemical shifts, and represented graphically through a recently developed method for visualising chemical shielding tensors (VIST). These results are further interpreted in terms of a 2D rigid rotor model of aromaticity and through an analysis of the natural transition orbitals involved in the triplet excited states showing good consistency between the different viewpoints. We believe that this work constitutes an important step in consolidating these varying viewpoints of electronically excited states.

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