• Title/Summary/Keyword: reorganization energy

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Theoretical Studies on Dicyanoanthracenes as Organic Semiconductor Materials: Reorganization Energy

  • Park, Young-Hee;Kim, Yun-Hi;Kwon, Soon-Ki;Koo, In-Sun;Yang, Ki-Yull
    • Bulletin of the Korean Chemical Society
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    • v.31 no.6
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    • pp.1649-1656
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    • 2010
  • Internal reorganization energy due to the structural relaxation in hole or electron hopping mechanism is one of the measurements of key indices in designing an organic thin film transistor (OTFT) for flexible display devices. In this study, the reorganization energies of dicyanoanthracenes for the hole and electron transfer were estimated by adiabatic potential energy surface and normal mode analysis method in order to examine the effect on the energies for the positional variation of the cyano substituents in the anthracene as a protocol of acenes to design an organic field effect transistor. The reorganization energy for the hole transfer was reduced considerably upon cyanation of anthracene, especially at the 9,10-positions of anthracene, and the origin of the reduction was interpreted in terms of understanding the coupling of vibrational modes to the hole transfer.

Theoretical investigation for the molecular structure and Charge transport property analysis of C16H16O3 as a candidate of liquid-crystal (액정 후보 물질로서 C16H16O3의 분자구조 및 전하이동성 특성분석에 관한 연구)

  • Park, Hye-Min;Kim, Seung-Joon
    • Analytical Science and Technology
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    • v.20 no.1
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    • pp.61-69
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    • 2007
  • The geometrical parameters, total and relative energies, vibrational frequencies, the HOMO-LUMO energy gap, and reorganization energies for the neutral molecule, anion, and cation of $C_{16}H_{16}O_3$ have been determined using density functional method (DFT). The highest level of theory employed in this study is $B3LYP/6-311G^{**}$. Harmonic vibrational frequencies were determined at the $B3LYP/6-311G^{**}$ level of theory. All positive vibrational frequencies were obtained to confirm minimum structures. The HOMO-LUMO energy gap and reorganization energies were calculated to predict the charge transport property of liquid-crystal.

Determination of Reorganization Energy from the Temperature Dependence of Electron Transfer Rate Constant for Hydroquinone-tethered Self-assembled Monolayers (SAMs)

  • Park, Won-choul;Hong, Hun-Gi
    • Bulletin of the Korean Chemical Society
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    • v.27 no.3
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    • pp.381-385
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    • 2006
  • The temperature dependence on the electron transfer rate constant $(k_{app})$ for hydroquinone redox center in $H_2Q(CH_2)_n$SH-SAMs (n = 1, 4, 6, 8, 10, and 12) on gold electrode was investigated to obtain reorganization energy $(\lambda)$ using Laviron’s formalism and Arrhenius plot of ln $[k_{app}/T^{1/2}]$ vs. T^{-1} based on the Marcus densityof-states model. All the symmetry factors measured for the SAMs were relatively close to unity and rarely varied to temperature change as expected. The electron tunneling constant $(\beta)$ determined from the dependence of the $k_{app}$ on the distance between the redox center and the electrode surface gives almost the same $\beta$ values which are quite insensitive to temperature change. Good linear relationship of Arrhenius plot for all $H_2Q(CH_2)_n$SH-SAMs on gold electrode was obtained in the temperature range from 273 to 328 K. The slopes n Arrhenius plot deduced that $\lambda$ of hydroquinone moiety is ca. 1.3-1.4 eV irrespectively of alkyl chain length of the electroactive SAM.

Theoretical Studies on 2-Hexylthieno[3,2-b]thiophene End-Capped Oligomers for Organic Semiconductor Materials

  • Park, Young-Hee;Kim, Yun-Hi;Kwon, Soon-Ki;Koo, In-Sun;Yang, Ki-Yull
    • Bulletin of the Korean Chemical Society
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    • v.33 no.4
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    • pp.1213-1219
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    • 2012
  • The reorganization energy and the spectroscopic properties of 2,6-bis(5'-hexyl-thieno[3,2-b]thiophene-2'- yl)naphthalene (DH-TNT) and 2,6-bis(5'-hexyl-thieno[3,2-b]thiophene-2'-yl)anthracene (DH-TAT), which are composed of an acene unit and alkylated thienothiophene on both sides, as organic materials for display devices were calculated and the results were compared with experimental values. The lower reorganization energy of the DH-TAT over the DH-TNT calculated by the density functional theory is attributed to a smaller vibrational distortion because of the heavier building block of DH-TAT, and it shows a good field effect performance over the DH-TNT. The calculated spectra and the other spectroscopic characteristic of the compounds are well consistent with those of observed results.

An Analysis on Electric Power Policy through ACMS Model : Focused on the Power Generation Subsidiary Company of the Korea Electric Power Corporation (ACMS 모형을 적용한 전력정책의 변동 분석 : 한국전력공사의 발전자회사를 중심으로)

  • Ji, Byoung-Seog;Kang, Seung-Jin
    • The Transactions of the Korean Institute of Electrical Engineers P
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    • v.65 no.1
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    • pp.31-40
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    • 2016
  • The purpose of this study is to dimensionally examine the factors of policy changes by applying the ACMS model to KEPCO's structural reorganization privatization policies and study its implications. As a result of the analysis, among the external variables that affect as a financial source or restriction to advocates, all areas except for the difference in opinion of the people as well as policy decision and effects of other subordinate systems were shown to be in an advantageous condition acting as a financial source to advocates of structural reorganization privatization. On the other hand, advocates affected by the external variables share a certain belief system in which the advocates of privatization share the justification of profitability while the advocates of collectivization share the justification of publicness. In these flows, the announcement of the privatization plan of public enterprises of the committee of planning and budgeting acts as a matter of contact which opens the windows for policy changes, and this window goes through ignition, explosion, and fixation which causes fierce interactions among advocates of both sides. Eventually, in accordance with the contents of excluding electricity(KEPCO) from the list for privatization the window for policy changes has closed and things have changed to a transitional KEPCO privatization policy. Based on this, the first implication is that non-official participants such as the people, social organizations, labor unions, etc. influence policy changes more than they did before. Secondly, in the process of policy changes, there is an order of boundary even in the fierce interactions between each advocate. Thirdly, specific variables can play various roles in complex policy phenomenon. Fourthly, a logical analysis using the ACMS model is possible in Korea as well. Fifthly, as a result of analyzing the change process of the KEPCO structural reorganization privatization policy through the ACMS model, not all matched with the main research results implied by the ACMS model.

A Scope of Functional Molecular Materials (기능성 분자재료의 발전 방향)

  • Shin, Dong-Myung;Kang, Dou-Yol
    • Proceedings of the KIEE Conference
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    • 1990.11a
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    • pp.136-138
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    • 1990
  • In developing, microscopic scale electrical and electronic devices, molecular level Insulators and functional electric conductors are fundamental. The properties of the electrical-insulating thin film materials are very much dependent on defects and electron transfer rate. There are number of companies which try to reduce defects and control electrical conductivity. Functional electrical conductors are more demanding subject in electrical fields. Reorganization energy around the sites that generate the electrons and holes are very important for the electron transfer in the organic thin layers.

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STUDY OF CONTACT ION PAIR DYNAMICS IN VIEW OF THE MOLECULAR SHAPES

  • Han, Chul-Hee
    • Journal of Photoscience
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    • v.3 no.3
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    • pp.147-151
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    • 1996
  • Dynamics of contact ion-pair between 1, 2, 4, 5-tetracyanobenzene anion and cation of biphenyl derivatives was investigated on the picosecond time scale. Solvent effect on the electron transfer was observed and electron transfer rates were examined using Marcus equation which contains distance dependence of the electron transfer rate in the frequency factor, along with the consideration of molecular shape. From the discussion based on disk model for molecular shape, contribution of interring torsional motion of biphenyl to the inner-sphere reorganization energy is strongly suggested, which leads to the physical explanation for the observed solvent effect on the rate of electron transfer.

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A Study on Substation Automation in Power System (전력계통의 변전소 자동화에 대한 연구)

  • Moon, Hyoung-Bae;Lim, Seong-Joo;Lee, Sang-Joong
    • Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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    • 2005.11a
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    • pp.119-124
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    • 2005
  • The deregulation of energy market, together with structure reorganization of vertically integrated companies in electrical utility requires efficient and reliable substation automation system. The problem of non-standards where other countries suffer through the SA points could be settled using IEC 61850 and hereby the coming SAS project can realize the system that characterize the telecommunication standards and function integration.

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Routing Techniques for Data Aggregation in Sensor Networks

  • Kim, Jeong-Joon
    • Journal of Information Processing Systems
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    • v.14 no.2
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    • pp.396-417
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    • 2018
  • GR-tree and query aggregation techniques have been proposed for spatial query processing in conventional spatial query processing for wireless sensor networks. Although these spatial query processing techniques consider spatial query optimization, time query optimization is not taken into consideration. The index reorganization cost and communication cost for the parent sensor nodes increase the energy consumption that is required to ensure the most efficient operation in the wireless sensor node. This paper proposes itinerary-based R-tree (IR-tree) for more efficient spatial-temporal query processing in wireless sensor networks. This paper analyzes the performance of previous studies and IR-tree, which are the conventional spatial query processing techniques, with regard to the accuracy, energy consumption, and query processing time of the query results using the wireless sensor data with Uniform, Gauss, and Skew distributions. This paper proves the superiority of the proposed IR-tree-based space-time indexing.

The Effect of Water in Four Adenine-Thymine and Three Guanine-Cytosine Pairs: Combining Quantum and Statistical Mechanics

  • Lee, Jinkeong;Ham, Sihyun
    • Proceeding of EDISON Challenge
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    • 2015.03a
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    • pp.151-155
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    • 2015
  • The molecular interactions between the nucleic acid bases and water molecules are important in organism. Despite Adenine-Thymine Hoogsteen base pair and Guanine-Cytosine Watson-Crick base pair have been demonstrated to be most stable in a gas phase, the effect of water on the stability of these base pairs remains elusive. Here we report the structural and thermodynamic characteristics on possible Adenine-Thymine and Guanine-Cytosine base pairs in a gas phase as well as in an aqueous phase by using quantum mechanical method and statistical mechanical calculations. First, we optimized the direct base-pair interaction energies of four Adenine-Thymine base pairs (Hoogsteen base pair, reverse Hoogsteen base pair, Watson-Crick base pair, and reverse Watson-Crick base pair) and three Guanine-Cytosine base pairs (GC1 base pair, GC2 base pair, and Watson Crick base pair) in a gas phase at the $B3LYP/6-31+G^{**}$ level. Then, the effect of solvent was quantified by the electronic reorganization energy and the solvation free energy by statistical mechanical calculations. Thereby, we discuss the effect of water on the stability of Adenine-Thymine and Guanine-Cytosine base pairs, and argue why Adenine-Thymine Watson-Crick base pair and Guanine-Cytosine Watson-Crick base pair are most stable in an aqueous environment.

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