{"created":"2023-06-20T13:20:14.478273+00:00","id":252,"links":{},"metadata":{"_buckets":{"deposit":"8c3dc878-cf87-4a30-9db6-e3264cf587bc"},"_deposit":{"created_by":1,"id":"252","owners":[1],"pid":{"revision_id":0,"type":"depid","value":"252"},"status":"published"},"_oai":{"id":"oai:ir.soken.ac.jp:00000252","sets":["2:427:9"]},"author_link":["0","0","0"],"item_1_creator_2":{"attribute_name":"著者名","attribute_type":"creator","attribute_value_mlt":[{"creatorNames":[{"creatorName":"白鳥, 和矢"}],"nameIdentifiers":[{}]}]},"item_1_creator_3":{"attribute_name":"フリガナ","attribute_type":"creator","attribute_value_mlt":[{"creatorNames":[{"creatorName":"シラトリ, カズヤ"}],"nameIdentifiers":[{}]}]},"item_1_date_granted_11":{"attribute_name":"学位授与年月日","attribute_value_mlt":[{"subitem_dategranted":"2008-03-19"}]},"item_1_degree_grantor_5":{"attribute_name":"学位授与機関","attribute_value_mlt":[{"subitem_degreegrantor":[{"subitem_degreegrantor_name":"総合研究大学院大学"}]}]},"item_1_degree_name_6":{"attribute_name":"学位名","attribute_value_mlt":[{"subitem_degreename":"博士（理学）"}]},"item_1_description_12":{"attribute_name":"要旨","attribute_value_mlt":[{"subitem_description":" Electrochemical processes have historically been investigated in a wide range of
interests in electrochemical cell, corrosion, membrane potential and analytical
technique. Their importance has extensively been recognized in recent years, for
example, in the context of energy conversion related to photoelectrochemical cells
based on advanced fabrication technology. To analyze these electrochemical processes,
it is required to clarify electronic structures of a system in electrochemical
environment. Nevertheless, it is computationally demanding to carry out
first-principles calculations of such electronic states. This is simply because
reactant-solvent and reactant-electrode interactions, which are completely absent in
isolated molecular systems, play an important role. Therefore, the electrochemical
processes have so far been studied within various numerical models at different levels
of theory. The problems in the electrochemical processes can be classified into two
parts. The first problem is difficulty in carrying out electronic structure calculations of
the reactant molecule at a constant chemical potential µ, and the other one is how to
appropriately describe the reactant-solvent and the reactant-electrode interactions.
The conventional ab initio calculations are directed toward obtaining electronic
structures at a constant number of electrons, N . Such ab initio calculations cannot be
straightforwardly applied to electronic structure calculations at a constant µ, in
which the number of electrons is not a suitable variable. Although several studies have
been devoted to development of the methods calculating electronic structures at a
constant µ, their methods are still substantially based on the constant N
calculations. Therefore, it is desirable to develop an alternative method to directly
calculate electronic structures at a constant µ. Finite-temperature density functional
theory (FTDFT) treats a system in a grand canonical ensemble average and thus one
can propose a numerical method based on FTDFT to describe electrochemical
processes.
In addition to the requirement for the electronic structure calculation at a constant
µ, reactant-solvent and reactant-electrode interactions should be considered in
electrochemical processes, as mentioned above. He primarily focuses on developing the FTDFT method of electronic structure calculation of reactant molecules at a constant
µ. Therefore, he approximates the solvent effects in terms of a simple continuum
model and limit electrochemical processes to outer-sphere ones in which the electrode
is treated as a reservoir with µ. It should be noted that the development of the
electronic structure calculation has nothing to do with the treatment of the
reactant-solvent interaction, so that the present FTDFT method can be
straightforwardly improved by employing more sophisticated procedures describing
the solvent effects.
In this thesis, he develops a method of the FTDFT ab initio quantum chemistry
calculations combined with a continuum solvent model and discuss the electronic
properties of molecules in electrochemical environment. The actual calculations are
carried out by solving the finite-temperature Kohn-Sham (KS) equation with the
GAMESS package of quantum chemistry programs in which the present numerical
methodology of FTDFT is implemented. The KS orbitals are expanded in terms of
Dunning's augmented correlation-consistent basis set (aug-cc-pVDZ).
He applies the present method to the electrochemical reaction,NO++e-↔ NO . The
Becke three-parameter hybrid exchange functional with the Lee-Yang-Parr correlation
functional (B3LYP) is used as the exchange-correlation potential. He does not
consider the temperature dependence of the exchange-correlation potential although
the potential in the FTDFT approach should depend on temperature in a narrow sense.
The solvent effects are treated at the level of conductor-like polarizable continuum
model (C-PCM), assuming the equilibrium condition between the solute and the
solvent. He gives the size of the cavity in C-PCM as a function of the molecular charge.
The calculation is carried out at the chemical potentials µ -3.40, -5.40, and -7.40 eV.
These values correspond to the electrode potentials v = -0.84, 1.16, and 3.16 V vs
SHE (standard hydrogen electrode), respectively. It has successfully been
demonstrated that the grand potential curve depends on µ, i.e., the electrode
potential. The calculation showed that the charge is a function of the chemical
otential and the internuclear distance of NO. The FTDFT/C-PCM approach has
proved to be a useful computational tool for electronic structure calculations at a
constant µ of a molecule interacting with solvent molecules.
Although the FTDFT/C-PCM method has succeeded in giving the reasonable results,
there are two problems to be addressed: the B3LYP functional is used uncritically and
the nonequilibrium solvation effect is not taken into account. These unsettled
problems might give rise to serious disadvantages in analysis of electrochemical
kinetics. Thus, he improves the FTDFT approach further by employing a different
functional and a different continuum solvent model, as mentioned bellow. This
improved FTDFT method is also applied to the electrochemical reaction
of NO++e-↔NO.
In the extension of the Hohenberg-Kohn theorem to the system with a fractional
number of electrons N by Perdew et al., they demonstrated that the energy
calculated by using DFT should show derivative discontinuity with respect to N .
However, it is known that the B3LYP functional does not reproduce the derivative
discontinuity condition. He alternatively employs the Becke exchange and
Lee-Yang-Parr correlation functional with a long-range correction (LC-BLYP). The
result obtained by using the LC-BLYP functional depends on the parameter ω that
divides the Coulomb operator into short-range and long-range parts. It has been found
that the B3LYP functional completely fails to describe the grand potential surface
whereas the LC-BLYP functional gives a proper grand potential surface if an
appropriate value of ω is taken. This is because the result of the LC-BLYP functional
with the optimal value of ω satisfies the requirement of the derivative discontinuity
with respect to N.
To treat the nonequilibrium solvation effect, he uses the extended self-consistent
reaction field (SCRF) model. This model allows considering the nonequilibrium
solvation effect by dividing solvent polarization into long-lived and short-lived
components. The calculated activation free energy, 12 kcal/mol, was in good agreement
with an experimental result, 11 kcal/mol, whereas the result obtained by using the
conventional SCRF model (i.e., not taking account of the nonequilibrium solvation
effect) gave considerably lower value, 3 kcal/mol. He has clearly shown that the
nonequilibrium solvation effect has a great influence on the electrochemical process
and the extended SCRF model significantly improves the calculated activation free
energy.
In summary, he has developed a computational method based on FTDFT combined
with a continuum solvent model to analyze electrochemical processes. The FTDFT
method allows calculating the electronic structures as a function of the chemical
potential. To apply the method to the studies of electrochemical kinetics, use of a
nonequilibrium solvation model and an exchange-correlation potential satisfying the
derivative discontinuity is crucially important. This study provides a powerful and
intuitive approach to analysis of electrochemical reactions.
","subitem_description_type":"Other"}]},"item_1_description_7":{"attribute_name":"学位記番号","attribute_value_mlt":[{"subitem_description":"総研大甲第1117号","subitem_description_type":"Other"}]},"item_1_select_14":{"attribute_name":"所蔵","attribute_value_mlt":[{"subitem_select_item":"有"}]},"item_1_select_8":{"attribute_name":"研究科","attribute_value_mlt":[{"subitem_select_item":"物理科学研究科"}]},"item_1_select_9":{"attribute_name":"専攻","attribute_value_mlt":[{"subitem_select_item":"07 構造分子科学専攻"}]},"item_1_text_10":{"attribute_name":"学位授与年度","attribute_value_mlt":[{"subitem_text_value":"2007"}]},"item_creator":{"attribute_name":"著者","attribute_type":"creator","attribute_value_mlt":[{"creatorNames":[{"creatorName":"SHIRATORI, Kazuya","creatorNameLang":"en"}],"nameIdentifiers":[{}]}]},"item_files":{"attribute_name":"ファイル情報","attribute_type":"file","attribute_value_mlt":[{"accessrole":"open_date","date":[{"dateType":"Available","dateValue":"2016-02-17"}],"displaytype":"simple","filename":"甲1117_要旨.pdf","filesize":[{"value":"387.7 kB"}],"format":"application/pdf","licensetype":"license_11","mimetype":"application/pdf","url":{"label":"要旨・審査要旨","url":"https://ir.soken.ac.jp/record/252/files/甲1117_要旨.pdf"},"version_id":"cb4f7aac-ac23-455d-9ac6-ba0867b8e23f"}]},"item_language":{"attribute_name":"言語","attribute_value_mlt":[{"subitem_language":"eng"}]},"item_resource_type":{"attribute_name":"資源タイプ","attribute_value_mlt":[{"resourcetype":"thesis","resourceuri":"http://purl.org/coar/resource_type/c_46ec"}]},"item_title":"Finite-temperature density functional approach to electrochemical reaction","item_titles":{"attribute_name":"タイトル","attribute_value_mlt":[{"subitem_title":"Finite-temperature density functional approach to electrochemical reaction"},{"subitem_title":"Finite-temperature density functional approach to electrochemical reaction","subitem_title_language":"en"}]},"item_type_id":"1","owner":"1","path":["9"],"pubdate":{"attribute_name":"公開日","attribute_value":"2010-02-22"},"publish_date":"2010-02-22","publish_status":"0","recid":"252","relation_version_is_last":true,"title":["Finite-temperature density functional approach to electrochemical reaction"],"weko_creator_id":"1","weko_shared_id":1},"updated":"2023-06-20T16:02:43.538364+00:00"}