東華大學圖書館 |

語系: 繁體中文

說明(常見問題)

回圖書館首頁

手機版館藏查詢

登入

回首頁

切換: 標籤 | MARC模式 | ISBD

FindBook

Google Book

Amazon

博客來

Semiempirical Methods for Excited States of Nanomaterials.

紀錄類型:	書目-電子資源 : Monograph/item
正題名/作者:	Semiempirical Methods for Excited States of Nanomaterials./
作者:	Cho, Yeongsu.
出版者:	Ann Arbor : ProQuest Dissertations & Theses, : 2021,
面頁冊數:	92 p.
附註:	Source: Dissertations Abstracts International, Volume: 83-03, Section: B.
Contained By:	Dissertations Abstracts International83-03B.
標題:	Computational chemistry. -
電子資源:	http://pqdd.sinica.edu.tw/twdaoapp/servlet/advanced?query=28717684
ISBN:	9798535599267

Semiempirical Methods for Excited States of Nanomaterials.
Cho, Yeongsu.

Semiempirical Methods for Excited States of Nanomaterials. - Ann Arbor : ProQuest Dissertations & Theses, 2021 - 92 p.

Source: Dissertations Abstracts International, Volume: 83-03, Section: B.

Thesis (Ph.D.)--Columbia University, 2021.

This item must not be sold to any third party vendors.

Density functional theory (DFT) provides an affordable computational tool to understand electronic structure of various molecules and solids. However, the use of DFT is still challenging to investigate nanomaterials of intermediate size that are too small to assume translational symmetry and too large to be considered as molecules. This thesis focuses on developing cost-effective but accurate computational methods for nanomaterials and using the methods to rationalize and predict experimental behaviors. A notable difference of a nanomaterial from its bulk counterpart is that its properties are exceptionally sensitive to the dielectric environment, requiring a proper treatment of the surrounding dielectrics for an accurate understanding. The consequences of heterogeneous dielectric screening on transition metal dichalcogenides are studied by developing a new theory based on classical electrostatics, which closely reproduced the band gaps and optical gaps calculated by the ab initio GW approximation and the Bethe-Salpeter equation (BSE). The relative insensitivity of the first optical transition energy observed by experiments was explained for the first time in terms of the cancellation effect of changes of the band gap and the exciton binding energy. The theory of heterogeneous dielectric environments is further developed to be used in an atomistic calculation of layered hybrid organic-inorganic lead halide perovskites via a tight-binding GW-BSE method. The binding energies of trions and biexcitons were also calculated using the stochastic variational method to give spectrum peak energies that show a good agreement with reported experimental measurements. Lastly, the tight-binding GW-BSE method is generalized into an atomistic, semiempirical approach to calculate the electronic structure and optical spectra of arbitrary nanomaterials, termed semiempirical GW (sGW) and BSE (sBSE).

ISBN: 9798535599267Subjects--Topical Terms:

3350019
Computational chemistry.
Subjects--Index Terms:

Density functional theory

Semiempirical Methods for Excited States of Nanomaterials.
LDR:03076nmm a2200373 4500 001 2348637
005 20220912135624.5
008 241004s2021 ||||||||||||||||| ||eng d
020 $a 9798535599267
035 $a (MiAaPQ)AAI28717684
035 $a AAI28717684
040 $a MiAaPQ $c MiAaPQ
100 1 $a Cho, Yeongsu. $3 3688007
245 1 0 $a Semiempirical Methods for Excited States of Nanomaterials.
260 1 $a Ann Arbor : $b ProQuest Dissertations & Theses, $c 2021
300 $a 92 p.
500 $a Source: Dissertations Abstracts International, Volume: 83-03, Section: B.
500 $a Advisor: Berkelbach, Timothy.
502 $a Thesis (Ph.D.)--Columbia University, 2021.
506 $a This item must not be sold to any third party vendors.
520 $a Density functional theory (DFT) provides an affordable computational tool to understand electronic structure of various molecules and solids. However, the use of DFT is still challenging to investigate nanomaterials of intermediate size that are too small to assume translational symmetry and too large to be considered as molecules. This thesis focuses on developing cost-effective but accurate computational methods for nanomaterials and using the methods to rationalize and predict experimental behaviors. A notable difference of a nanomaterial from its bulk counterpart is that its properties are exceptionally sensitive to the dielectric environment, requiring a proper treatment of the surrounding dielectrics for an accurate understanding. The consequences of heterogeneous dielectric screening on transition metal dichalcogenides are studied by developing a new theory based on classical electrostatics, which closely reproduced the band gaps and optical gaps calculated by the ab initio GW approximation and the Bethe-Salpeter equation (BSE). The relative insensitivity of the first optical transition energy observed by experiments was explained for the first time in terms of the cancellation effect of changes of the band gap and the exciton binding energy. The theory of heterogeneous dielectric environments is further developed to be used in an atomistic calculation of layered hybrid organic-inorganic lead halide perovskites via a tight-binding GW-BSE method. The binding energies of trions and biexcitons were also calculated using the stochastic variational method to give spectrum peak energies that show a good agreement with reported experimental measurements. Lastly, the tight-binding GW-BSE method is generalized into an atomistic, semiempirical approach to calculate the electronic structure and optical spectra of arbitrary nanomaterials, termed semiempirical GW (sGW) and BSE (sBSE).
590 $a School code: 0054.
650 4 $a Computational chemistry. $3 3350019
650 4 $a Condensed matter physics. $3 3173567
650 4 $a Electrostatics. $3 542300
650 4 $a Approximation. $3 3560410
650 4 $a Nanomaterials. $3 3558221
650 4 $a Energy. $3 876794
650 4 $a Semiconductors. $3 516162
650 4 $a Experiments. $3 525909
650 4 $a Geometry. $3 517251
650 4 $a Symmetry. $3 536815
650 4 $a Nanotechnology. $3 526235
653 $a Density functional theory
653 $a Binding energies of trions
653 $a Bethe-Salpeter equation
653 $a Electronic structure
690 $a 0219
690 $a 0611
690 $a 0791
690 $a 0652
710 2 $a Columbia University. $b Chemistry. $3 2102233
773 0 $t Dissertations Abstracts International $g 83-03B.
790 $a 0054
791 $a Ph.D.
792 $a 2021
793 $a English
856 4 0 $u http://pqdd.sinica.edu.tw/twdaoapp/servlet/advanced?query=28717684