Beers, William W.

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Authority KeyName Variants
1c89a04e-6c10-4bbc-aa46-351cb200d813
  • Beers, William W. (3)
  • Beers, William W (1)
Projects
Chongqing University of Posts and Telecommunications and the National Foreign Experts Program for “Belt and Road Initiative” Innovative Talent Exchange [Grant No. DL2021035001L] European Regional Development Fund [TK141]
Program for the Foreign Experts [Grant No. W2017011] Chinese National Foreign Experts Program for “Belt and Road Initiative” Innovative Talent Ex- change [Grant No. DL2021035001 L]
CQUPT Program for Foreign Ex- perts [Grant No. W2017011] Estonian Research Council [grant PUT PRG111]
Estonian Research Council [Grant PUT PRG111] Estonian Research Council [PRG 2031]
Ministry of Education, Science and Technological Development, Republic of Serbia, Grant no. 451-03-68/2020-14/200017 (University of Belgrade, Institute of Nuclear Sciences 'Vinča', Belgrade-Vinča) National Natural Science Foundation of China [52161135110 and 12274048]
National Natural Science Foundation of China [Grant No. 52161135110 and 12274048] National Natural Science Foundation of China [Grant Nos. 52161135110 and 12274048]
NCN [project 2018/31/B/ST4/00924] NCN [project 2018/31/B/ST4/00924 and 2021/40/Q/ST5/ 00336]
Overseas Talents Plan of Chongqing Association for Science and Technology [Grant Nos. 2021[70] and 2022[60]] Overseas Talents Workstation of Chongqing Association for Science and Technology, National Science Centre [project SHENG–2 no. 2021/40/Q/ST5/ 00336 and NCN project 2018/31/B/ST4/00924]
Polish National Science Center OPUS [2019/33/B/ST8/02142] Polish NCN [2021/40/Q/ST5/00336]
verseas Talents Plan of Chongqing Association for Science and Technology, China (2022[60])

Author's Bibliography

Narrowband red luminescence of tetrahedral-site Fe3+ In Ca8Mg(SiO4)4Cl2

Srivastava, Alok M; Suchocki, Andrzej; Bulyk, Lev-Ivan; Zhydachevskyy, Yaroslav; Brik, Mikhail G.; Beers, William W; Cohen, Willian E

(2024)

TY  - JOUR
AU  - Srivastava, Alok M
AU  - Suchocki, Andrzej
AU  - Bulyk, Lev-Ivan
AU  - Zhydachevskyy, Yaroslav
AU  - Brik, Mikhail G.
AU  - Beers, William W
AU  - Cohen, Willian E
PY  - 2024
UR  - https://vinar.vin.bg.ac.rs/handle/123456789/13124
AB  - We have measured the excitation and emission spectra, and lifetime for Fe3+ in the Ca8Mg(SiO4)4Cl2 compound. The spectroscopic data of the ferric ion (Fe3+) is interpreted within the framework of the Tanabe-Sugano crystal field theory for ions with the d5 electronic configuration. Quantitative evaluation of the Racah parameters B and C and the crystal field parameter (10 Dq) is provided. The emission and excitation data are consistent for Fe3+ in a tetrahedral-site occupancy. The red emission is assigned to the 4T1 (4G)→6A1 (6S) crystal field transition. The remarkable feature of the luminescence is the positioning of the emission band; it is centered at 623 nm with a Full Width at Half Maximum of 51 nm. To the best of our knowledge this is one of the highest energy emission for the tetrahedral-site Fe3+ ion. The practical implication of this spectral power distribution is discussed. The temperature dependency of the luminescence lifetime and emission intensity are reported.
T2  - Optical Materials
T1  - Narrowband red luminescence of tetrahedral-site Fe3+ In Ca8Mg(SiO4)4Cl2
VL  - 150
SP  - 115290
DO  - 10.1016/j.optmat.2024.115290
ER  - 
@article{
author = "Srivastava, Alok M and Suchocki, Andrzej and Bulyk, Lev-Ivan and Zhydachevskyy, Yaroslav and Brik, Mikhail G. and Beers, William W and Cohen, Willian E",
year = "2024",
abstract = "We have measured the excitation and emission spectra, and lifetime for Fe3+ in the Ca8Mg(SiO4)4Cl2 compound. The spectroscopic data of the ferric ion (Fe3+) is interpreted within the framework of the Tanabe-Sugano crystal field theory for ions with the d5 electronic configuration. Quantitative evaluation of the Racah parameters B and C and the crystal field parameter (10 Dq) is provided. The emission and excitation data are consistent for Fe3+ in a tetrahedral-site occupancy. The red emission is assigned to the 4T1 (4G)→6A1 (6S) crystal field transition. The remarkable feature of the luminescence is the positioning of the emission band; it is centered at 623 nm with a Full Width at Half Maximum of 51 nm. To the best of our knowledge this is one of the highest energy emission for the tetrahedral-site Fe3+ ion. The practical implication of this spectral power distribution is discussed. The temperature dependency of the luminescence lifetime and emission intensity are reported.",
journal = "Optical Materials",
title = "Narrowband red luminescence of tetrahedral-site Fe3+ In Ca8Mg(SiO4)4Cl2",
volume = "150",
pages = "115290",
doi = "10.1016/j.optmat.2024.115290"
}
Srivastava, A. M., Suchocki, A., Bulyk, L., Zhydachevskyy, Y., Brik, M. G., Beers, W. W.,& Cohen, W. E.. (2024). Narrowband red luminescence of tetrahedral-site Fe3+ In Ca8Mg(SiO4)4Cl2. in Optical Materials, 150, 115290.
https://doi.org/10.1016/j.optmat.2024.115290
Srivastava AM, Suchocki A, Bulyk L, Zhydachevskyy Y, Brik MG, Beers WW, Cohen WE. Narrowband red luminescence of tetrahedral-site Fe3+ In Ca8Mg(SiO4)4Cl2. in Optical Materials. 2024;150:115290.
doi:10.1016/j.optmat.2024.115290 .
Srivastava, Alok M, Suchocki, Andrzej, Bulyk, Lev-Ivan, Zhydachevskyy, Yaroslav, Brik, Mikhail G., Beers, William W, Cohen, Willian E, "Narrowband red luminescence of tetrahedral-site Fe3+ In Ca8Mg(SiO4)4Cl2" in Optical Materials, 150 (2024):115290,
https://doi.org/10.1016/j.optmat.2024.115290 . .

Intensity of the Eu3+ hypersensitive transition in isostructural phosphate and vanadate compounds

Srivastava, Alok M.; Brik, Mikhail G.; Beers, William W.; Ma, Chong-Geng; Piasecki, Michal; Cohen, William E.

(2023)

TY  - JOUR
AU  - Srivastava, Alok M.
AU  - Brik, Mikhail G.
AU  - Beers, William W.
AU  - Ma, Chong-Geng
AU  - Piasecki, Michal
AU  - Cohen, William E.
PY  - 2023
UR  - https://vinar.vin.bg.ac.rs/handle/123456789/10610
AB  - A comparative study of Eu3+ luminescence in an isostructural series of phosphate and vanadate compounds correlates the hypersensitivity of the 5D0→7F2 transition to the covalence and polarizability of the (XO4)3- (X = P, V) polyanion. The intensity of this transition, as measured by the ratio, [Formula presented], is always higher in the vanadate system [R (PO4)3-« R (VO4)3-]. Electronic energy band structure of these systems establishes higher covalence and polarizability of the (VO4)3- polyanion, which is due to strong V 3 d - O 2p covalent interaction via hybridization. The difference in the intensity of the hypersensitive transition between the phosphate and vanadate systems is consistent with the prediction of the ligand dipolar polarization model for the 4f-4f dipolar intensities. Our analysis supports the polarizability of (XO4)3- (X = P, V) over local site distortion effects as the intensity enhancing mechanism of the 5D0→7F2 transition. It is pointed out that the hybridization effect that serves as the source of the intensity of hypersensitive transition also accounts for the origin of second harmonic generation (SHG) in Li3VO4 and its absence in Li3PO4. © 2023 Elsevier B.V.
T2  - Journal of Luminescence
T1  - Intensity of the Eu3+ hypersensitive transition in isostructural phosphate and vanadate compounds
VL  - 257
DO  - 10.1016/j.jlumin.2023.119709
ER  - 
@article{
author = "Srivastava, Alok M. and Brik, Mikhail G. and Beers, William W. and Ma, Chong-Geng and Piasecki, Michal and Cohen, William E.",
year = "2023",
abstract = "A comparative study of Eu3+ luminescence in an isostructural series of phosphate and vanadate compounds correlates the hypersensitivity of the 5D0→7F2 transition to the covalence and polarizability of the (XO4)3- (X = P, V) polyanion. The intensity of this transition, as measured by the ratio, [Formula presented], is always higher in the vanadate system [R (PO4)3-« R (VO4)3-]. Electronic energy band structure of these systems establishes higher covalence and polarizability of the (VO4)3- polyanion, which is due to strong V 3 d - O 2p covalent interaction via hybridization. The difference in the intensity of the hypersensitive transition between the phosphate and vanadate systems is consistent with the prediction of the ligand dipolar polarization model for the 4f-4f dipolar intensities. Our analysis supports the polarizability of (XO4)3- (X = P, V) over local site distortion effects as the intensity enhancing mechanism of the 5D0→7F2 transition. It is pointed out that the hybridization effect that serves as the source of the intensity of hypersensitive transition also accounts for the origin of second harmonic generation (SHG) in Li3VO4 and its absence in Li3PO4. © 2023 Elsevier B.V.",
journal = "Journal of Luminescence",
title = "Intensity of the Eu3+ hypersensitive transition in isostructural phosphate and vanadate compounds",
volume = "257",
doi = "10.1016/j.jlumin.2023.119709"
}
Srivastava, A. M., Brik, M. G., Beers, W. W., Ma, C., Piasecki, M.,& Cohen, W. E.. (2023). Intensity of the Eu3+ hypersensitive transition in isostructural phosphate and vanadate compounds. in Journal of Luminescence, 257.
https://doi.org/10.1016/j.jlumin.2023.119709
Srivastava AM, Brik MG, Beers WW, Ma C, Piasecki M, Cohen WE. Intensity of the Eu3+ hypersensitive transition in isostructural phosphate and vanadate compounds. in Journal of Luminescence. 2023;257.
doi:10.1016/j.jlumin.2023.119709 .
Srivastava, Alok M., Brik, Mikhail G., Beers, William W., Ma, Chong-Geng, Piasecki, Michal, Cohen, William E., "Intensity of the Eu3+ hypersensitive transition in isostructural phosphate and vanadate compounds" in Journal of Luminescence, 257 (2023),
https://doi.org/10.1016/j.jlumin.2023.119709 . .
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Orbital Hybridization and Hypersensitivity of Eu3+ in YXO4 (X=P, As, V)

Srivastava, Alok M.; Brik, Mikhail; Beers, William W.; Lou, B.; Ma, C.-G.; Piasecki, Michal; Cohen, William E.

(2023)

TY  - JOUR
AU  - Srivastava, Alok M.
AU  - Brik, Mikhail
AU  - Beers, William W.
AU  - Lou, B.
AU  - Ma, C.-G.
AU  - Piasecki, Michal
AU  - Cohen, William E.
PY  - 2023
UR  - https://vinar.vin.bg.ac.rs/handle/123456789/11170
AB  - A comparative study of Eu3+ ion luminescence in YXO4 (X=P, As, V) with the tetragonal zircon structure is conducted in relation to the intensity of the hypersensitivity 5D0 → 7F2 Δ J = 2 transition. Both the asymmetry ratio, R = I 5 D 0 − 7 F 2 I 5 D 0 − 7 F 1 , and the Judd-Ofelt Ω2 intensity parameter increases in the order YPO4 < YAsO4 < YVO4. This correlation is interpreted qualitatively in terms of the covalency and polarizability of (XO4)3−, which increases in the order (PO4)3− < (AsO4)3− < (VO4)3−. The trend is supported by the results of electronic band structure calculations of the three compounds which establish the strength of hybridization between the X cation and the oxygen 2p states. The electronic structure of YAsO4 is calculated to probe the covalence of As-O bonding. The increasing oscillator strength of the Eu3+5D0 → 7F2 transition in going from YPO4 to YAsO4 to YVO4 is consistent with the expectation of ligand dipolar polarization model for hypersensitivity which states that the oscillator strength of the 5D0 → 7F2 transition is proportional to the square of the ligand dipolar polarizability. The connection between the mechanism of hypersensitivity and second harmonic generation (SHG) is presented. © 2023 The Electrochemical Society (“ECS”). Published on behalf of ECS by IOP Publishing Limited.
T2  - ECS Journal of Solid State Science and Technology
T1  - Orbital Hybridization and Hypersensitivity of Eu3+ in YXO4 (X=P, As, V)
VL  - 12
IS  - 6
SP  - 066001
DO  - 10.1149/2162-8777/acd80f
ER  - 
@article{
author = "Srivastava, Alok M. and Brik, Mikhail and Beers, William W. and Lou, B. and Ma, C.-G. and Piasecki, Michal and Cohen, William E.",
year = "2023",
abstract = "A comparative study of Eu3+ ion luminescence in YXO4 (X=P, As, V) with the tetragonal zircon structure is conducted in relation to the intensity of the hypersensitivity 5D0 → 7F2 Δ J = 2 transition. Both the asymmetry ratio, R = I 5 D 0 − 7 F 2 I 5 D 0 − 7 F 1 , and the Judd-Ofelt Ω2 intensity parameter increases in the order YPO4 < YAsO4 < YVO4. This correlation is interpreted qualitatively in terms of the covalency and polarizability of (XO4)3−, which increases in the order (PO4)3− < (AsO4)3− < (VO4)3−. The trend is supported by the results of electronic band structure calculations of the three compounds which establish the strength of hybridization between the X cation and the oxygen 2p states. The electronic structure of YAsO4 is calculated to probe the covalence of As-O bonding. The increasing oscillator strength of the Eu3+5D0 → 7F2 transition in going from YPO4 to YAsO4 to YVO4 is consistent with the expectation of ligand dipolar polarization model for hypersensitivity which states that the oscillator strength of the 5D0 → 7F2 transition is proportional to the square of the ligand dipolar polarizability. The connection between the mechanism of hypersensitivity and second harmonic generation (SHG) is presented. © 2023 The Electrochemical Society (“ECS”). Published on behalf of ECS by IOP Publishing Limited.",
journal = "ECS Journal of Solid State Science and Technology",
title = "Orbital Hybridization and Hypersensitivity of Eu3+ in YXO4 (X=P, As, V)",
volume = "12",
number = "6",
pages = "066001",
doi = "10.1149/2162-8777/acd80f"
}
Srivastava, A. M., Brik, M., Beers, W. W., Lou, B., Ma, C.-G., Piasecki, M.,& Cohen, W. E.. (2023). Orbital Hybridization and Hypersensitivity of Eu3+ in YXO4 (X=P, As, V). in ECS Journal of Solid State Science and Technology, 12(6), 066001.
https://doi.org/10.1149/2162-8777/acd80f
Srivastava AM, Brik M, Beers WW, Lou B, Ma C, Piasecki M, Cohen WE. Orbital Hybridization and Hypersensitivity of Eu3+ in YXO4 (X=P, As, V). in ECS Journal of Solid State Science and Technology. 2023;12(6):066001.
doi:10.1149/2162-8777/acd80f .
Srivastava, Alok M., Brik, Mikhail, Beers, William W., Lou, B., Ma, C.-G., Piasecki, Michal, Cohen, William E., "Orbital Hybridization and Hypersensitivity of Eu3+ in YXO4 (X=P, As, V)" in ECS Journal of Solid State Science and Technology, 12, no. 6 (2023):066001,
https://doi.org/10.1149/2162-8777/acd80f . .

Chemical Pressure Effects on the Stokes Shift of Bi3+ Luminescence in Orthorhombic Perovskites

Srivastava, Alok M.; Brik, Mikhail G.; Beers, William W.; Cohen, William E.

(2022)

TY  - JOUR
AU  - Srivastava, Alok M.
AU  - Brik, Mikhail G.
AU  - Beers, William W.
AU  - Cohen, William E.
PY  - 2022
UR  - https://vinar.vin.bg.ac.rs/handle/123456789/10601
AB  - The relationship between the Stokes shift of Bi3+ emission and the volume of the unit-cell in two series of orthorhombic perovskites, LnB 3+O3 (Ln = La, Gd, Y; B 3+ = Al, In, Ga) and AB 4+O3 (A = Ca, Sr; B 4+ = Zr, Sn) is explored. The Stokes shift increases linearly with increasing cell volume. This is explained qualitatively by the lattice chemical pressure acting on the Bi3+ ion. The degree of Bi3+ ion off-centering displacement, which is due to the stereochemical activity of the lone-pair electrons (6 s2), is controlled by the chemical pressure. A small cell suppresses the off-centering displacement to produce a small Stokes shift of emission by limiting the excited state structural distortion. In large cell, the off-centering displacement is more easily accommodated. The elimination of ground state distortion in the excited state gives larger Stokes shift of emission. These qualitative arguments are supplemented by recent first-principles calculations on Bi3+ luminescence in these perovskites. The Bi3+ luminescence in SrZrO3, previously assigned to emission from the D-state, is now assigned to the localized 3P0,1 → 1S0 transition. The energy of the 1S0 → 3P1 transition is correlated with the covalence of the BO6/2 perovskite framework. Discussion on the effective ionic radius of the Bi3+ ion in these perovskites is presented.
T2  - ECS Journal of Solid State Science and Technology
T1  - Chemical Pressure Effects on the Stokes Shift of Bi3+ Luminescence in Orthorhombic Perovskites
VL  - 11
IS  - 9
SP  - 096003
DO  - 10.1149/2162-8777/ac915b
ER  - 
@article{
author = "Srivastava, Alok M. and Brik, Mikhail G. and Beers, William W. and Cohen, William E.",
year = "2022",
abstract = "The relationship between the Stokes shift of Bi3+ emission and the volume of the unit-cell in two series of orthorhombic perovskites, LnB 3+O3 (Ln = La, Gd, Y; B 3+ = Al, In, Ga) and AB 4+O3 (A = Ca, Sr; B 4+ = Zr, Sn) is explored. The Stokes shift increases linearly with increasing cell volume. This is explained qualitatively by the lattice chemical pressure acting on the Bi3+ ion. The degree of Bi3+ ion off-centering displacement, which is due to the stereochemical activity of the lone-pair electrons (6 s2), is controlled by the chemical pressure. A small cell suppresses the off-centering displacement to produce a small Stokes shift of emission by limiting the excited state structural distortion. In large cell, the off-centering displacement is more easily accommodated. The elimination of ground state distortion in the excited state gives larger Stokes shift of emission. These qualitative arguments are supplemented by recent first-principles calculations on Bi3+ luminescence in these perovskites. The Bi3+ luminescence in SrZrO3, previously assigned to emission from the D-state, is now assigned to the localized 3P0,1 → 1S0 transition. The energy of the 1S0 → 3P1 transition is correlated with the covalence of the BO6/2 perovskite framework. Discussion on the effective ionic radius of the Bi3+ ion in these perovskites is presented.",
journal = "ECS Journal of Solid State Science and Technology",
title = "Chemical Pressure Effects on the Stokes Shift of Bi3+ Luminescence in Orthorhombic Perovskites",
volume = "11",
number = "9",
pages = "096003",
doi = "10.1149/2162-8777/ac915b"
}
Srivastava, A. M., Brik, M. G., Beers, W. W.,& Cohen, W. E.. (2022). Chemical Pressure Effects on the Stokes Shift of Bi3+ Luminescence in Orthorhombic Perovskites. in ECS Journal of Solid State Science and Technology, 11(9), 096003.
https://doi.org/10.1149/2162-8777/ac915b
Srivastava AM, Brik MG, Beers WW, Cohen WE. Chemical Pressure Effects on the Stokes Shift of Bi3+ Luminescence in Orthorhombic Perovskites. in ECS Journal of Solid State Science and Technology. 2022;11(9):096003.
doi:10.1149/2162-8777/ac915b .
Srivastava, Alok M., Brik, Mikhail G., Beers, William W., Cohen, William E., "Chemical Pressure Effects on the Stokes Shift of Bi3+ Luminescence in Orthorhombic Perovskites" in ECS Journal of Solid State Science and Technology, 11, no. 9 (2022):096003,
https://doi.org/10.1149/2162-8777/ac915b . .
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