Comprehensive photoelectron spectroscopic study of anionic clusters of anthracene and its alkyl derivatives: Electronic structures bridging molecules to bulk

Naoto Ando, Masaaki Mitsui, Atsushi Nakajima

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Abstract

The evolution of the electronic structure of molecular aggregates is investigated using anion photoelectron (PE) spectroscopy for anionic clusters of anthracene (Ac) and its alkyl derivatives: 1-methylanthracene (1MA), 2-methylanthracene (2MA), 9-methylanthracene (9MA), 9,10-dimethylanthracene (DMA), and 2-tert-butylanthracene (2TBA). For their monomer anions (n=1), electron affinities are confined to the range from 0.47 to 0.59 eV and are well reproduced by density functional theory calculations, showing the isoelectronic character of these molecules. For cluster anions (n=2-100) of Ac and 2MA, two types of isomers I and II coexist over a wide size range: isomers I and II-1 (4≤n<30) or isomers I and II-2 (n∼40 for Ac and n∼55 for 2MA). However, for the other alkyl-substituted Ac cluster anions (i.e., 1MA, 9MA, DMA, and 2TBA), only isomer I is exclusively formed, and neither isomer II-1 nor II-2 is observed. The vertical detachment energies (VDEs) of isomer I in all the anionic clusters depend almost linearly on n-13. In contrast, the VDEs of isomers II-1 (n14) and II-2 (n=40-100), appeared only in Ac and 2MA cluster anions, remain constant with n and are ∼0.5 eV lower than those of isomer I. The PE spectra revealed the characteristics of each isomer: isomer I possesses a monomeric anion core that is gradually embedded into the interior of the cluster with increasing n. On the other hand, isomers II-1 and II-2 possess a multimeric (perhaps tetrameric) anion core, but they differ in the number of layers from which they are made up; monolayer (isomer II-1) and multilayers (isomer II-2) of a two-dimensionally ordered, finite herringbone-type structure, in which electron attachment produces only little geometrical rearrangement. Moreover, the agreement of the constant VDEs of isomer II-2 with the bulk data demonstrates the largely localized nature of the electronic polarization around the excess charge in a crystal-like environment, where about 50 molecules provide a charge stabilization energy comparable to the bulk.

Original languageEnglish
Article number234305
JournalJournal of Chemical Physics
Volume127
Issue number23
DOIs
Publication statusPublished - 2007

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anthracene
Photoelectrons
Isomers
Electronic structure
photoelectrons
isomers
electronic structure
Derivatives
Molecules
Anions
molecules
anions
detachment
Electron affinity
energy
electron attachment
Photoelectron spectroscopy
electron affinity
Density functional theory
Monolayers

ASJC Scopus subject areas

  • Atomic and Molecular Physics, and Optics

Cite this

@article{32f094f6c29a42449a7c815ae74dc968,
title = "Comprehensive photoelectron spectroscopic study of anionic clusters of anthracene and its alkyl derivatives: Electronic structures bridging molecules to bulk",
abstract = "The evolution of the electronic structure of molecular aggregates is investigated using anion photoelectron (PE) spectroscopy for anionic clusters of anthracene (Ac) and its alkyl derivatives: 1-methylanthracene (1MA), 2-methylanthracene (2MA), 9-methylanthracene (9MA), 9,10-dimethylanthracene (DMA), and 2-tert-butylanthracene (2TBA). For their monomer anions (n=1), electron affinities are confined to the range from 0.47 to 0.59 eV and are well reproduced by density functional theory calculations, showing the isoelectronic character of these molecules. For cluster anions (n=2-100) of Ac and 2MA, two types of isomers I and II coexist over a wide size range: isomers I and II-1 (4≤n<30) or isomers I and II-2 (n∼40 for Ac and n∼55 for 2MA). However, for the other alkyl-substituted Ac cluster anions (i.e., 1MA, 9MA, DMA, and 2TBA), only isomer I is exclusively formed, and neither isomer II-1 nor II-2 is observed. The vertical detachment energies (VDEs) of isomer I in all the anionic clusters depend almost linearly on n-13. In contrast, the VDEs of isomers II-1 (n14) and II-2 (n=40-100), appeared only in Ac and 2MA cluster anions, remain constant with n and are ∼0.5 eV lower than those of isomer I. The PE spectra revealed the characteristics of each isomer: isomer I possesses a monomeric anion core that is gradually embedded into the interior of the cluster with increasing n. On the other hand, isomers II-1 and II-2 possess a multimeric (perhaps tetrameric) anion core, but they differ in the number of layers from which they are made up; monolayer (isomer II-1) and multilayers (isomer II-2) of a two-dimensionally ordered, finite herringbone-type structure, in which electron attachment produces only little geometrical rearrangement. Moreover, the agreement of the constant VDEs of isomer II-2 with the bulk data demonstrates the largely localized nature of the electronic polarization around the excess charge in a crystal-like environment, where about 50 molecules provide a charge stabilization energy comparable to the bulk.",
author = "Naoto Ando and Masaaki Mitsui and Atsushi Nakajima",
year = "2007",
doi = "10.1063/1.2805185",
language = "English",
volume = "127",
journal = "Journal of Chemical Physics",
issn = "0021-9606",
publisher = "American Institute of Physics Publising LLC",
number = "23",

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TY - JOUR

T1 - Comprehensive photoelectron spectroscopic study of anionic clusters of anthracene and its alkyl derivatives

T2 - Electronic structures bridging molecules to bulk

AU - Ando, Naoto

AU - Mitsui, Masaaki

AU - Nakajima, Atsushi

PY - 2007

Y1 - 2007

N2 - The evolution of the electronic structure of molecular aggregates is investigated using anion photoelectron (PE) spectroscopy for anionic clusters of anthracene (Ac) and its alkyl derivatives: 1-methylanthracene (1MA), 2-methylanthracene (2MA), 9-methylanthracene (9MA), 9,10-dimethylanthracene (DMA), and 2-tert-butylanthracene (2TBA). For their monomer anions (n=1), electron affinities are confined to the range from 0.47 to 0.59 eV and are well reproduced by density functional theory calculations, showing the isoelectronic character of these molecules. For cluster anions (n=2-100) of Ac and 2MA, two types of isomers I and II coexist over a wide size range: isomers I and II-1 (4≤n<30) or isomers I and II-2 (n∼40 for Ac and n∼55 for 2MA). However, for the other alkyl-substituted Ac cluster anions (i.e., 1MA, 9MA, DMA, and 2TBA), only isomer I is exclusively formed, and neither isomer II-1 nor II-2 is observed. The vertical detachment energies (VDEs) of isomer I in all the anionic clusters depend almost linearly on n-13. In contrast, the VDEs of isomers II-1 (n14) and II-2 (n=40-100), appeared only in Ac and 2MA cluster anions, remain constant with n and are ∼0.5 eV lower than those of isomer I. The PE spectra revealed the characteristics of each isomer: isomer I possesses a monomeric anion core that is gradually embedded into the interior of the cluster with increasing n. On the other hand, isomers II-1 and II-2 possess a multimeric (perhaps tetrameric) anion core, but they differ in the number of layers from which they are made up; monolayer (isomer II-1) and multilayers (isomer II-2) of a two-dimensionally ordered, finite herringbone-type structure, in which electron attachment produces only little geometrical rearrangement. Moreover, the agreement of the constant VDEs of isomer II-2 with the bulk data demonstrates the largely localized nature of the electronic polarization around the excess charge in a crystal-like environment, where about 50 molecules provide a charge stabilization energy comparable to the bulk.

AB - The evolution of the electronic structure of molecular aggregates is investigated using anion photoelectron (PE) spectroscopy for anionic clusters of anthracene (Ac) and its alkyl derivatives: 1-methylanthracene (1MA), 2-methylanthracene (2MA), 9-methylanthracene (9MA), 9,10-dimethylanthracene (DMA), and 2-tert-butylanthracene (2TBA). For their monomer anions (n=1), electron affinities are confined to the range from 0.47 to 0.59 eV and are well reproduced by density functional theory calculations, showing the isoelectronic character of these molecules. For cluster anions (n=2-100) of Ac and 2MA, two types of isomers I and II coexist over a wide size range: isomers I and II-1 (4≤n<30) or isomers I and II-2 (n∼40 for Ac and n∼55 for 2MA). However, for the other alkyl-substituted Ac cluster anions (i.e., 1MA, 9MA, DMA, and 2TBA), only isomer I is exclusively formed, and neither isomer II-1 nor II-2 is observed. The vertical detachment energies (VDEs) of isomer I in all the anionic clusters depend almost linearly on n-13. In contrast, the VDEs of isomers II-1 (n14) and II-2 (n=40-100), appeared only in Ac and 2MA cluster anions, remain constant with n and are ∼0.5 eV lower than those of isomer I. The PE spectra revealed the characteristics of each isomer: isomer I possesses a monomeric anion core that is gradually embedded into the interior of the cluster with increasing n. On the other hand, isomers II-1 and II-2 possess a multimeric (perhaps tetrameric) anion core, but they differ in the number of layers from which they are made up; monolayer (isomer II-1) and multilayers (isomer II-2) of a two-dimensionally ordered, finite herringbone-type structure, in which electron attachment produces only little geometrical rearrangement. Moreover, the agreement of the constant VDEs of isomer II-2 with the bulk data demonstrates the largely localized nature of the electronic polarization around the excess charge in a crystal-like environment, where about 50 molecules provide a charge stabilization energy comparable to the bulk.

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