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Zhao X, Li Y, Zhao X. Density Functional Theory Study of the Point Defects on KDP (100) and (101) Surfaces. MOLECULES (BASEL, SWITZERLAND) 2022; 27:molecules27249014. [PMID: 36558145 PMCID: PMC9785294 DOI: 10.3390/molecules27249014] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/29/2022] [Revised: 12/11/2022] [Accepted: 12/13/2022] [Indexed: 12/24/2022]
Abstract
Surface defects are usually associated with the formation of other forms of expansion defects in crystals, which have an impact on the crystals' growth quality and optical properties. Thereby, the structure, stability, and electronic structure of the hydrogen and oxygen vacancy defects (VH and VO) on the (100) and (101) growth surfaces of KDP crystals were studied by using density functional theory. The effects of acidic and alkaline environments on the structure and properties of surface defects were also discussed. It has been found that the considered vacancy defects have different properties on the (100) and (101) surfaces, especially those that have been reported in the bulk KDP crystals. The (100) surface has a strong tolerance for surface VH and VO defects, while the VO defect causes a large lattice relaxation on the (101) surface and introduces a deep defect level in the band gap, which damages the optical properties of KDP crystals. In addition, the results show that the acidic environment is conducive to the repair of the VH defects on the surface and can eliminate the defect states introduced by the surface VO defects, which is conducive to improving the quality of the crystal surface and reducing the defect density. Our study opens up a new way to understand the structure and properties of surface defects in KDP crystals, which are different from the bulk phase, and also provides a theoretical basis for experimentally regulating the surface defects in KDP crystals through an acidic environment.
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Affiliation(s)
- Xiaoji Zhao
- State Key Lab of Crystal Materials, Institute of Crystal Materials, Shandong University, Jinan 250100, China
| | - Yanlu Li
- State Key Lab of Crystal Materials, Institute of Crystal Materials, Shandong University, Jinan 250100, China
- Correspondence: (Y.L.); (X.Z.)
| | - Xian Zhao
- State Key Lab of Crystal Materials, Institute of Crystal Materials, Shandong University, Jinan 250100, China
- Center for Optics Research and Engineering of Shandong University, Shandong University, Qingdao 266237, China
- Correspondence: (Y.L.); (X.Z.)
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Liu J, Wang J, Chen Y. Theoretical investigation of weak absorption and laser induced damage in YCOB crystal. CrystEngComm 2022. [DOI: 10.1039/d2ce00465h] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Weak absorption and laser-induced damage in crystal have been extensively studied, but the mechanism of these phenomena is still not well understood. Herein, we investigated the weak absorption and laser-induced...
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Aswathappa S, Palaniyasan E, Dhas Sathiyadhas SJ, Jayaperumal KS, Paramasivam S, Sonachalam A, Dhas Sathiyadhas Amalapushpam MB. Shock wave induced defect engineering on structural and optical properties of pure and dye doped potassium dihydrogen phosphate crystals. Z KRIST-CRYST MATER 2020. [DOI: 10.1515/zkri-2020-0017] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Abstract
Based on the importance of the shock recovery experiments, the authors report the structural and optical properties of pure and 0.001 M dye-doped potassium dihydrogen phosphate (KDP) crystals for virgin and shock wave loaded samples. Rhodamine B and Methylene blue dyes are selected as dopants to be doped with KDP crystal for the present investigation. The test crystals of pure and doped KDP crystals are grown by slow evaporation technique and cut and polished crystals of (200) face are used for the present investigation. Table-top pressure driven shock tube is utilized for the shock wave generation and the used functional Mach number is 1.7. Virgin and shock wave loaded test crystals’ surface morphology, structural properties and optical transmissions are observed using optical microscope, powder X-ray diffractometer and UV-Visible spectrometer, respectively. Crystalline nature and optical transmission of pure and doped KDP crystals are found to have reduced by the impact of shock waves. It occurs due to the enhancement of defect concentration on the surface of the test crystals. From the observed results, we assert that the pure KDP crystal is relatively more stable to shock wave induced damage compared to doped KDP crystals as reflected by structural and optical studies.
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Affiliation(s)
- Sivakumar Aswathappa
- Department of Physics , Abdul Kalam Research Center, Sacred Heart College , Tirupattur , Vellore , 635601 , Tamil Nadu , India
| | - Eniya Palaniyasan
- Department of Physics , Periyar University , Salem , 636011 , Tamil Nadu , India
| | | | | | - Sivaprakash Paramasivam
- Centre for High Pressure Research, School of Physics , Bharathidasan University , Tiruchirapalli , 620024 , Tamil Nadu , India
| | - Arumugam Sonachalam
- Centre for High Pressure Research, School of Physics , Bharathidasan University , Tiruchirapalli , 620024 , Tamil Nadu , India
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Liu C, Min F, Liu L, Chen J. Density Functional Theory Study of Water Molecule Adsorption on the α-Quartz (001) Surface with and without the Presence of Na +, Mg 2+, and Ca 2. ACS OMEGA 2019; 4:12711-12718. [PMID: 31460393 PMCID: PMC6682150 DOI: 10.1021/acsomega.9b01570] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/28/2019] [Accepted: 07/12/2019] [Indexed: 06/10/2023]
Abstract
Adsorption of the single water molecule on the α-quartz (001) surface with and without the presence of Na+, Mg2+ and Ca2+ was analyzed utilizing the density functional theory method. Our results demonstrate that the optimal adsorption configuration of the single water molecule on the α-quartz (001) surface lies in the bridge being configured with two formed hydrogen bonds. These were Os-Hw and Hs-Ow (s and w represent, respectively, surface and water molecules), while the main hydrogen bond is Hw-Os. Furthermore, the corresponding adsorption energy was ∼-72.60 kJ/mol. In this study, the presence of metal ions helped to deflect the spatial position of the water molecule, and the distance between Ow and Hs was altered significantly. Furthermore, the charge transfer between the interacting atoms increased in the presence of metal ions, wherein the effects of Ca2+ and Na+ proved to be significant compared to Mg2+. Finally, it emerged that metal ions interacted with the water molecule and were subsequently adsorbed on the α-quartz (001) surface. This occurred due to the electrostatic attraction, consequently impacting the hydration characteristics of the quartz surface.
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Understanding Cement Hydration of Cemented Paste Backfill: DFT Study of Water Adsorption on Tricalcium Silicate (111) Surface. MINERALS 2019. [DOI: 10.3390/min9040202] [Citation(s) in RCA: 40] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Understanding cement hydration is of crucial importance for the application of cementitious materials, including cemented paste backfill. In this work, the adsorption of a single water molecule on an M3-C3S (111) surface is investigated using density functional theory (DFT) calculations. The adsorption energies for 14 starting geometries are calculated and the electronic properties of the reaction are analysed. Two adsorption mechanisms, molecular adsorption and dissociative adsorption, are observed and six adsorption configurations are found. The results indicate that spontaneous dissociative adsorption is energetically favored over molecular adsorption. Electrons are transferred from the surface to the water molecule during adsorption. The density of states (DOS) reveals the bonding mechanisms between water and the surface. This study provides an insight into the adsorption mechanism at an atomic level, and can significantly promote the understanding of cement hydration within such systems.
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Adsorption mechanisms of metal ions on the potassium dihydrogen phosphate (1 0 0) surface: A density functional theory-based investigation. J Colloid Interface Sci 2018; 522:256-263. [DOI: 10.1016/j.jcis.2018.03.073] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2018] [Revised: 03/07/2018] [Accepted: 03/21/2018] [Indexed: 11/23/2022]
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