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Hiroki Kojima, Taiyo Inada, Shigenori Matsushima, Junko Ishii, Kenji Obata, [Masao Arai](https://orcid.org/0000-0003-0088-5649)

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[First-principles study on electronic structure and optical properties of Mn-doped Ba<sub>3</sub>V<sub>2</sub>O<sub>8</sub>](https://mdr.nims.go.jp/datasets/da99e5cf-e923-47fa-8ff2-921cac662da5)

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First-principles study on electronic structure and optical properties of Mn-doped Ba3V2O8FULL PAPERFirst-principles study on electronic structure and optical propertiesof Mn-doped Ba3V2O8Hiroki Kojima1,2, Taiyo Inada1,2, Shigenori Matsushima3,4,³, Junko Ishii3, Kenji Obata3 and Masao Arai51Advanced Course of Creative Engineering, National Institute of Technology, Kitakyushu College,5–20–1 Shii, Kokuraminami-ku, Kitakyushu, 802–0985, Japan2Department of Interdisciplinary Engineering, Faculty of Engineering, Kyushu University,6–1 Kasugakoen, Kasuga, Fukuoka 816–8580, Japan3Department of Creative Engineering, National Institute of Technology, Kitakyushu College,5–20–1 Shii, Kokuraminami-ku, Kitakyushu, 802–0985, Japan4Department of Collaborative Interdisciplinary Engineering Sciences, Faculty of Engineering Science, Kyushu University,6–1 Kasugakoen, Kasuga, Fukuoka 816–8580, Japan5Center for Basic Research on Materials, National Institute for Materials Science (NIMS),1–1 Namiki, Tsukuba, Ibaraki 305–0044, JapanThe electronic structure and optical properties of Mn-doped Ba3V2O8, a promising cobalt-free pigment, areinvestigated using first-principles calculations to elucidate the microscopic mechanism of its vivid blue colora-tion. Structural optimization done by the pseudopotential method, combined with high-precision all-electronband calculations (FLAPW method) reveals the interplay between local lattice distortion and optical response.The results demonstrate that the substitution of V5+ with Mn5+ (3d2) introduces spin-polarized impurity stateswithin the band gap. These mid-gap states arise intrinsically from the crystal field splitting of the Mn orbitalsinto occupied e and unoccupied t2 levels. Crucially, the [MnO4]3¹ tetrahedra undergo significant structuraldistortion, lowering the local symmetry from Td to C1. While this distortion is not the primary origin of theimpurity levels, it plays a decisive role in governing the optical transition probabilities. The symmetry breakingenhances the hybridization between Mn 3d and O 2p orbitals, relaxing the selection rules for d–d transitions.Consequently, a distinct absorption peak arises at approximately 1.6 eV, which is responsible for the blue color,alongside a charge-transfer transition around 3.3 eV. Furthermore, the distortion induces strong optical anisot-ropy, manifested as a significant splitting of the dielectric function along the principal optical axes. This studyprovides a comprehensive theoretical framework linking the local geometric distortion to the intense andanisotropic optical response of Mn-doped Ba3V2O8.Key-words : Ba3V2O8, Mn-doped Ba3V2O8, First-principles calculation[Received November 10, 2025; Accepted January 27, 2026; Published online March 5, 2026]1. IntroductionCeramic pigments have historically relied on hazardousmetallic elements such as hexavalent chromium (Cr),cadmium (Cd), antimony (Sb), and lead (Pb) to achievevibrant colors. In recent years, however, growing concernsabout the detrimental effects of these metals on humanhealth and the environment have prompted calls for strin-gent international regulations on their use, as exemplifiedby Europe’s RoHS Directive.1) The most widely utilizedblue ceramic pigment, cobalt blue (CoAl2O4), serves as acase in point. While CoAl2O4 offers excellent blue color-ation, easy synthesis, and superior resistance to heat, acid,and alkali, cobalt (Co) is not only a rare and expensiveelement but also poses significant toxicity risks. For thesecompelling reasons—spanning public health, environmen-tal preservation, and economic viability—the developmentof cobalt-free blue ceramic pigments has become an urgentscientific and industrial challenge.Recently, Smith et al. reported that YIn1¹xMnxO3 ex-hibits a vivid blue color, presenting it as a potential sub-stitute for CoAl2O4.2) Unfortunately, indium (In), which isin high demand for transparent conductive films, is evenrarer and more expensive than Co, rendering its widespread application as a pigment economically impractical.An alternative and promising route involves oxides andphosphates doped with pentavalent manganese (Mn5+),which have been repeatedly shown to exhibit blue colora-tion.3–6) Among these materials, Mn-doped Ba3V2O8, dis-covered by Guo et al.,7) is particularly noteworthy as apotential CoAl2O4 replacement due to its superior thermalstability and durability.A key factor contributing to the promise of this material³ Corresponding author: S. Matsushima; E-mail: smatsu@kct.ac.jpJournal of the Ceramic Society of Japan 134 [4] 303-310 2026DOI https://doi.org/10.2109/jcersj2.25153 JCS-Japan©2026 The Ceramic Society of Japan 303This is an Open Access article distributed under the terms of the Creative Commons Attribution License (https://creativecommons.org/licenses/by-nc/4.0/),which permits use, distribution, and reproduction in any medium for non-commercial purposes, provided the original work is properly cited.https://doi.org/10.2109/jcersj2.25153https://creativecommons.org/licenses/by-nc/4.0/is the high degree of similarity between the V5+ and Mn5+ions that occupy the tetrahedral sites in the Ba3V2O8 hostlattice. These ions share the same valence state and haveonly a small difference in ionic radius. Furthermore, bothreadily adopt a tetrahedral coordination with four sur-rounding oxygen atoms. This crystallographic compatibil-ity facilitates a wide range of manganese solid solutionconcentrations, which in turn enables continuous tuning ofthe material’s color tone.Despite its potential, a fundamental understanding ofthe solid-state electronic structures of both the undopedBa3V2O8 unit cell and the Mn-doped Ba3V2O8 supercell,which are intrinsically linked to the coloration mechanism,remains elusive. Therefore, this study aims to comprehen-sively elucidate these electronic structures by performingfirst-principles band calculations, thereby providing atheoretical foundation for the material’s observed opticalproperties in details. Some preliminary data and interpre-tations were previously published elsewhere.8) In thispaper, we present revised figures and extended datasets,along with newly obtained insights that were not includedin the previous report.2. Computational methodsThe initial crystallographic information for undopedBa3V2O8 was sourced from literature values registered inthe ICSD database.9) The Ba3V2O8 unit cell belongs to thespace group R3-m (No. 166) and features five distinctWyckoff positions occupied by Ba1, Ba2, V, O1, and O2,as depicted in Fig. 1(a). Furthermore, Fig. 1(b) presentsthe first Brillouin zone of Ba3V2O8 primitive unit cell.Our computational approach involved a two-step proc-ess. First, structural optimizations were performed usingthe CASTEP (Cambridge Sequential Total Energy Package)program,10) a first-principles molecular dynamics packagewell-suited for efficient geometry relaxation. During theoptimization of undoped Ba3V2O8, the R3-m space groupsymmetry was maintained. The exchange–correlation inter-action was treated within the generalized gradient approx-imation (GGA) using the PBE functional.11,12) Conver-gence criteria for the optimization were stringently set asfollows: a total energy change of 1.0 © 10¹5 eV/atom, amaximum atomic force of 3.0 © 10¹2 eV/¡, a maximumdisplacement of 1.0 © 10¹3¡, and a maximum stress of5.0 © 10¹2 GPa. A plane-wave basis set with a cutoffenergy of 340 eV was employed, and the valence electronswere described using Vanderbilt-type non-local ultra-softpseudopotentials.13) Integration in the reciprocal space ofthe first Brillouin zone was performed using a 5 © 5 © 2Monkhorst-Pack mesh,14) yielding 7 irreducible k-points.For the Mn-doped system, a 2 © 2 © 1 supercell was con-structed from the optimized undoped unit cell, and one Vatom was subsequently substituted with an Mn atom. Dueto the symmetry breaking induced by the dopant, the spacegroup of the system was treated as P1. In this case, onlythe atomic coordinates of the supercell were optimized,while the lattice parameters were fixed to those of theundoped host to simulate a dilute doping condition. Thesame GGA functional, convergence criteria, and cutoffenergy were used, while k-point sampling was restrictedto the ¥-point, a common practice for large supercellcalculations.Following structural optimization, electronic-structureand optical-property calculations were carried out usingWIEN2k,15,16) which implements the full-potential line-arized augmented plane wave plus local orbital(FLAPW+lo) method. This choice was motivated by theneed for highly accurate all-electron wavefunctions toanalyze optical absorption in direct relation to the complexdielectric function and density of states (DOS). Unlikepseudopotential methods, WIEN2k provides precise pro-jected DOS (PDOS) and momentum matrix elements be-tween occupied and unoccupied states, which are essen-tial for interpreting absorption features above the valenceband. The hexagonal lattice parameters optimized byCASTEP were adopted, and atomic coordinates were con-verted to the rhombohedral representation for WIEN2kinput. The basis set consisted of linear combinations ofspherical harmonics within the Muffin-Tin (MT) regionsand plane waves in the interstitial region. For undopedBa3V2O8, the MT sphere radii were set to 2.50, 1.68, and1.52 a.u. for Ba, V, and O, respectively. The plane waveBaVO(a) (b)Fig. 1. Crystal structure of Ba3V2O8 (R3-m) and the Brillouin zone of its primitive unit cell. High-symmetrypoints are shown as fractional coordinates: ¥(0, 0, 0), L(0.5000, 0, 0), B1(0.5000, 0.2038, ¹0.2038), B(0.7962,0.5000, 0.2038), Z(0.5000, 0.5000, 0.5000), X(0.3519, 0, ¹0.3519), Q(0.6481, 0.3519, 0), F(0.5000, 0.5000, 0),P1(0.6481, 0.6481, 0.2038), P(0.7962, 0.3519, 0.3519).Kojima et al.: First-principles study on electronic structure and optical properties of Mn-doped Ba3V2O8JCS-Japan304cutoff was defined by RMT © Kmax = 7.0, and 44 k-pointswere used for sampling. For the Mn-doped supercell, theMT radii were 5.45, 1.76, 1.68, and 1.51 a.u. for Ba, Mn,V, and O, respectively, with a plane wave cutoff of RMT ©Kmax = 5.0 and 54 k-points. The exchange–correlationinteraction was consistently treated using the GGAfunctional.The optical properties were derived from the complexdielectric function tensor, ¾(½) = ¾1(½) + i¾2(½).17) Theimaginary part, ¾2(½), was computed using the sum-over-states approach based on momentum matrix elementsbetween occupied and unoccupied states, while ¾1(½) wasobtained via the Kramers–Kronig relation. To ensure theconvergence of the optical spectra and eliminate numericalartifacts arising from k-point discretization, a dense k-mesh(resulting in 128 k-points) was employed for the opticalproperties calculation of Mn-doped Ba3V2O8 supercell. Inaddition, the upper energy limit (Emax) for the band cal-culation was set to 5.0Ry (68.03 eV). Consequently, amaximum of 1102 energy bands for the undoped Ba3V2O8were included in the calculation, which comprises 571occupied bands. In contrast, the Mn-doped Ba3V2O8 sys-tem required considering 4599 bands at most, and thenumber of occupied bands was 4182. The absorption coef-ficient I(½) was estimated using the following equation;Ið½Þ ¼ ðffiffiffi2p½=cÞffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffi¾1ð½Þ2 þ ¾2ð½Þ2q� ¾1ð½Þ� �1=2ð1Þwhere c is the speed of light in a vacuum.18) The calculatedspectra were broadened using Lorentzian functions tofacilitate comparison with experimental observations.3. Results and discussionTable 1 presents the lattice parameters and atomic coor-dinates for undoped Ba3V2O8 before and after structuraloptimization, with all values reported in a hexagonal repre-sentation. The optimization led to minor changes in thelattice parameters: the a-axis increased by approximately1.4%, and the c-axis increased by roughly 0.9%. Thisslight overestimation of lattice constants is a well-knowncharacteristic of the GGA functional and indicates that ourstructural model is physically sound.19) A detailed com-parison of the local coordination environments is providedin Table 2, which lists the metal-oxygen bond distancesfor the optimized structures of both undoped Ba3V2O8 andthe Mn-doped supercell. In the undoped host, each V atomis tetrahedrally coordinated by four oxygen atoms, withtwo distinct V–O distances. Upon substitution of V withMn, all Mn–O bond distances are found to be longer thantheir V–O counterparts. Furthermore, the difference be-tween the longest and shortest Mn–O distances is greaterthan that for the V–O bonds, suggesting an increase ingeometric distortion. This observation is corroborated bythe bond angle analysis in Table 3, which compares sixdistinct O–V (or Mn)–O angles within the [VO4]3¹ and[MnO4]3¹ tetrahedra. The angular distribution confirmsthat the [VO4]3¹ tetrahedron more closely approaches anTable 1. Lattice constants and atomic coordinates of Ba3V2O8 unit cell before and after structural optimizationa [¡] c [¡]atom sitelabelatom sitefract xatom sitefract yatom sitefract zBefore structuraloptimization5.7843 21.3274Ba1 0.0000 0.0000 0.0000Ba2 0.0000 0.0000 0.2051V1 0.0000 0.0000 0.4063O1 0.0000 0.0000 0.3279O2 0.1614 ¹0.1614 0.5655After structuraloptimization5.8676 21.5183Ba1 0.0000 0.0000 0.0000Ba2 0.0000 0.0000 0.2056V1 0.0000 0.0000 0.4072O1 0.0000 0.0000 0.3279O2 0.1604 ¹0.1604 0.5659Table 2. Bond distances (Ba1–O, Ba2–O, V–O, Mn–O) ofBa3V2O8 unit cell and Mn-doped Ba3V2O8 supercell after struc-tural optimizationBa3V2O8Mn-dopedBa3V2O8Ba1–O Ba2–O V–O Mn–OBond length (¡)2.7913 © 6 2.6297 1.7079 1.74372.8607 © 3 1.7292 © 3 1.77002.9911 © 6 1.77011.7708Table 3. Comparison of bond angles in [VO4]3¹ and [MnO4]3¹tetrahedra[VO4] [MnO4]Bond angle (°)109.41 108.03109.41 109.22109.41 109.22109.53 109.23109.53 109.23109.53 111.83Journal of the Ceramic Society of Japan 134 [4] 303-310 2026 JCS-Japan305ideal regular tetrahedron than the [MnO4]3¹ unit does.Collectively, the results in Tables 2 and 3 provide clearevidence that the [MnO4]3¹ tetrahedron is structurallymore distorted than the original [VO4]3¹ tetrahedron itreplaces.Figure 2 displays the calculated electronic band struc-ture of undoped Ba3V2O8. For the energy band calculation,highly symmetric k-points within the first Brillouin zonewere investigated as indicated in the literature,20) and fourdirections—¥–L–B1, B–Z–¥–X, Q–F–P1–Z, and L–P—were selected. The calculation reveals that the valenceband maximum (VBM) is located at the Z point, while theconduction band minimum (CBM) resides at the L point,classifying undoped Ba3V2O8 as an indirect band gapsemiconductor. Although standard GGA functionals typi-cally underestimate electronic band gaps,21,22) the com-puted value of 3.6 eV shows excellent agreement with theexperimental optical gap of 3.59 eV.7) Such agreement invanadate systems has been observed elsewhere and isoften attributed to a fortuitous error cancellation unique tothe V 3d–O 2p charge-transfer nature, or to the fact thatthe experimental optical gap includes significant excitonicbinding energies not captured in the single-particle GGAgap.23,24) Regardless of the absolute value, our focusremains on the relative changes in electronic structureinduced by Mn doping, which are reliably described at thislevel of theory. To ensure a meaningful comparison be-tween the electronic structures of undoped and Mn-dopedBa3V2O8, the energy axes were aligned using the Ba 5pcore-level states as a common reference. Figure 3 showsthe DOS of undoped Ba3V2O8. The site-projected DOSpresented here corresponds to the total density of statesintegrated within the muffin-tin sphere of each atomic spe-cies, which encompasses the contributions from all angularmomentum components. To ensure a clear physical inter-pretation, all DOS data are consistently normalized peratom. Analysis of the DOS confirms that the valence bandis predominantly composed of O 2p states, while the lowerpart of the conduction band is mainly derived from V 3dstates. The splitting observed in the V 3d states is a directconsequence of the crystal field imposed by the [VO4]3¹tetrahedral environment. The introduction of Mn dramat-ically alters this electronic landscape, as shown in Fig. 4,which illustrates the total DOS (TDOS) and Mn-relatedPDOS for the Mn-doped supercell. The most strikingfeature is the appearance of new impurity levels within thefundamental band gap of Ba3V2O8, originating from theMn 3d states. A comparison between the spin-up and spin-down channels reveals that the up-spin peak lies at a lowerenergy, indicating that this is the majority spin states andthat the system is spin-polarized. Specifically, the major-ity-spin Mn 3d states form impurity levels within the hostgap which are split into distinct occupied and unoccupiedbands. The lower-energy component of the spin-up statesis completely occupied by electrons, and the Fermi level(E = 0) is pinned precisely at the maximum of this occu-pied level. The energy difference between these mid-gapstates and the VBM is smaller than the photon energies ofvisible light. This electronic configuration suggests that theincorporation of Mn enables not only intra-atomic d–dtransitions between the occupied and unoccupied Mn 3dstates but also charge-transfer (CT) type absorption fromthe O 2p-dominated valence band to these Mn 3d states.These modifications to the electronic structure manifestdirectly in the optical properties. Figure 5 presents the cal-culated real and imaginary parts of the complex dielectricfunction, ¾1(½) and ¾2(½), for both undoped and Mn-doped Ba3V2O8. As a hexagonal crystal, undoped Ba3V2O8is optically uniaxial, characterized by two independentdielectric tensor components (xx and zz). In contrast, theMn-doped supercell, with its lower P1 space group sym-metry, becomes optically biaxial, possessing six tensorcomponents (three diagonal and three off-diagonal). Whilethe static refractive indices [¾1(0)] are similar for bothsystems, the absorptive part, ¾2(½), reveals critical dif-ferences. The overall shape of the ¾2(½) curve for thedoped system resembles the undoped one, but with thecrucial addition of two new features: a small, broad peakaround 1.6 eV and a more pronounced peak near 3.3 eV,both directly attributable to the presence of Mn. Based onthe DOS analysis, the absorption at 1.6 eV is assigned tothe spin-allowed d–d transitions within the Mn 3d mani-fold, while the peak at 3.3 eV corresponds to the charge-transfer (CT) transitions from O 2p to Mn 3d states.These features are more clearly resolved in the opticalabsorption spectra I(½), shown in Fig. 6. UndopedBa3V2O8 exhibits a sharp absorption onset around 3.6 eV,corresponding to interband transitions from the valence tothe conduction band. Conversely, the Mn-doped systemdisplays distinct absorption peaks at the same energiesidentified in the ¾2(½) spectrum. Since the Mn-doped sys-tem possesses low symmetry (P1), the dielectric functionis a tensor with non-zero off-diagonal components in thecrystallographic coordinate system. However, consider-ing that ceramic pigments are practically utilized in pow-der form consisting of randomly oriented crystallites, themacroscopic optical properties are best described by con-sidering the optical response along the principal axes andtheir polycrystalline average. Therefore, we diagonalizedthe calculated frequency-dependent complex dielectric ten-Fig. 2. Calculated energy band structure of Ba3V2O8 primitiveunit cell.Kojima et al.: First-principles study on electronic structure and optical properties of Mn-doped Ba3V2O8JCS-Japan306sor at each energy point to obtain the eigenvalues along thethree principal optical axes. Based on these principaldielectric functions, we determined the absorption coef-ficients ¡1(½), ¡2(½), and ¡3(½), and corresponding toeach principal axis, as well as the orientation-averagedabsorption spectrum.Figure 6 also includes the absorption spectrum calcu-lated for the Mn-doped structure prior to structural opti-mization to investigate the influence of local distortion.The “unoptimized” structure is defined as the host Ba3V2O8supercell (2 © 2 © 1) where one V atom is simply substi-tuted by Mn without relaxing the atomic coordinates, thuspreserving the quasi-ideal tetrahedral environment. Com-paring the optimized and unoptimized spectra reveals astriking difference. In the unoptimized structure, theabsorption intensity in the visible region is low, and theanisotropy is weak. However, when the structural dis-tortion is introduced through optimization, the absorptionpeak originating from the transition around 1.6 eV is dras-tically enhanced. Furthermore, the splitting among thethree principal components ¡1(½), ¡2(½), and ¡3(½) ex-pands significantly. The spectrum originating from theCT absorption around 3.3 eV also becomes distinct. Thisbehavior indicates that the optical anisotropy and the inten-sity of the transitions are intrinsically linked. The largesplitting of the principal components in the optimizedFig. 4. Total density of states (TDOS) and Mn 3d projecteddensity of states (PDOS) for the Mn-doped Ba3V2O8 supercell.The dashed line indicates the Fermi level (EF).Fig. 3. Total density of states (TDOS) and site-projected DOS for pristine Ba3V2O8: TDOS, Ba1, Ba2, V, O1,and O2. The dashed line marks the Fermi level (EF).Journal of the Ceramic Society of Japan 134 [4] 303-310 2026 JCS-Japan307(a) Ba3V2O8 unit cell(b) Mn-doped Ba3V2O8 supercellFig. 5. Complex dielectric function of Ba3V2O8 unit cell and Mn-doped Ba3V2O8 supercell.(a) Undoped(b) Mn-doped (optimized)(c) Mn-doped (unoptimized)Fig. 6. Optical absorption coefficients of Ba3V2O8 unit cell and Mn-doped Ba3V2O8 supercell.Kojima et al.: First-principles study on electronic structure and optical properties of Mn-doped Ba3V2O8JCS-Japan308structure is the physical manifestation of the significantoff-diagonal terms present in the original lattice coordinatesystem. These results indicate that the introduction of Mnonto the V site not only forms split 3d levels within theband gap but also that the vivid blue color is effectively“switched on” by the local distortion of the [MnO4]3¹ unit.To provide a microscopic understanding of the absorp-tion features observed in the principal absorption coef-ficients, we analyzed the PDOS of the Mn atom in thelocal coordinate system (Fig. 7). In a perfect Td field, theMn 3d orbitals split into a lower-energy doubly degeneratee set (dz2, dx2¹y2) and a higher-energy triply degenerate t2set (dxy, dyz, dzx). Since Mn5+ has a 3d2 configuration, thetwo electrons occupy the lower e states. As shown inFig. 7, the occupied states near the Fermi level (E µ 0 eV)are predominantly of e character, while the unoccupiedstates around 1.6 eV correspond to the t2 orbitals. Thefundamental origin of the coloration lies in the transitionbetween these crystal-field-split levels. In an ideal centro-symmetric or perfectly tetrahedral environment, electric-dipole transitions between d states (d–d transitions) areparity-forbidden by the Laporte selection rule. If the localsymmetry were perfectly Td, the transition probabilitywould be negligible, as confirmed by the unoptimizedspectrum in Fig. 6. However, as evidenced by our struc-tural optimization, the [MnO4]3¹ tetrahedron undergoessignificant distortion (C1 symmetry). This symmetry break-ing is the decisive factor. It allows for the mixing of theodd-parity O 2p ligand orbitals into the even-parity Mn 3dstates (p–d hybridization). This hybridization relaxes thestrict selection rules, imparting a finite and significantoscillator strength to the nominally forbidden e ¼ t2 tran-sition. It is this symmetry-lowering induced hybridizationthat generates the intrinsic absorption moment. Conse-quently, even when the macroscopic optical properties areaveraged over random orientations as in a powder sample,the absorption peak at 1.6 eV remains robust and distinct.The distortion “activates” the optical transition across thevisible range, resulting in the vivid blue reflection ob-served in the Mn-doped Ba3V2O8 pigment.4. ConclusionIn conclusion, this study has provided a comprehen-sive theoretical framework to understand the electronicand optical properties of Mn-doped Ba3V2O8. Our first-principles calculations demonstrated that the substitutionof vanadium with manganese introduces Mn 3d impuritystates within the band gap of the host material. These mid-gap states arise intrinsically from the 3d2 electronic con-figuration of the Mn5+ ion, where the occupied e states andunoccupied t2 states are separated by the crystal fieldsplitting. Furthermore, the structural relaxation revealedthat the [MnO4]3¹ tetrahedron undergoes significant dis-tortion compared to the ideal geometry. This structuraldistortion plays a critical role not in creating the impuritylevels, but in governing the optical transition probabilities.The lowering of local symmetry enhances the hybridiza-tion between Mn 3d and O 2p orbitals, thereby relaxingthe optical selection rules. This symmetry-breaking mech-anism “activates” the nominally forbidden d–d transition,imparting it with finite oscillator strength. Consequently,a characteristic absorption peak at 1.6 eV emerges andremains robust even in the orientation-averaged spectrumrepresenting the powder form of the pigment. Ultimately,this work elucidates that while the Mn5+ electronic con-figuration dictates the potential for color centers, the locallattice distortion is the key trigger that intensifies theoptical absorption, giving rise to the vivid blue colorationof Mn-doped Ba3V2O8.References1) European Parliament and Council, Directive 2002/95/EC of the European Parliament and of the Council of 27January 2003 on the restriction of the use of certainhazardous substances in electrical and electronic equip-ment. Official Journal of the European Union, L37, 19–23 (2003).2) A. E. Smith, M. C. Comstock and M. A. Subramanian,Dyes Pigments 133, 214 (2016).3) E. A. Medina, J. Li, J. K. Sralick and M. A.Subramanian, Solid State Sci. 52, 97 (2016).4) S. Laha, S. Tamilarasan, S. Natarajan and J.Fig. 7. Projected density of states for individual Mn 3d orbitalsand the total O 2p states integrated over oxygen sites O1 throughO4 in the Mn-doped Ba3V2O8 supercell.Journal of the Ceramic Society of Japan 134 [4] 303-310 2026 JCS-Japan309Gopalakrishnan, Inorg. Chem. 55, 3508 (2016).5) S. W. Kim, G. E. Sim, J. Y. Pck, J. H. Son, T. Hasegawa,K. Toda and D. S. Bae, Dyes Pigments 139, 344 (2017).6) Y. Wang, H. Lei, P. Jiang, L. Liu, K. Cui and W. Cao,Ceram. Int. 47, 686 (2021).7) H. Guo, L. Yuan, S. Wang and C. Hou, Ceram. Int. 50,3110 (2024).8) H. Kojima, J. Ishii and S. Matsushima, Research Reportof Kitakyushu National College of Technology 58, 21(2024) [in Japanese].9) S. Fop, J. A. Dawson, D. N. Tawse, M. G. Skellern,J. M. S. Skakle and A. C. Mclaughlin, Chem. Mater. 34,8190 (2022).10) V. Milman, B. Winkler, J. A. White, C. J. Pickard, M. C.Payne, E. V. Akhmatskaya and R. H. Nobes, Int. J.Quantum Chem. 77, 895910 (2000).11) J. P. Perdew and Y. Wang, Phys. Rev. B 45, 13244(1992).12) J. P. Perdew, K. Burke and M. Ernzerhof, Phys. Rev.Lett. 77, 38653868 (1996).13) D. Vanderbilt, Phys. Rev. B 41, 7892 (1990).14) H. J. Monkhorst and J. D. Pack, Phys. Rev. B 13, 5188(1976).15) P. Blaha, K. Schwarz, G. K. H. Madsen, D. Kvasnickaand J. Luitz, in “WIEN2k, An Augmented PlaneWave + Local Orbitals Program for Calculating CrystalProperties”, Ed. by K. Schwarz, Techn. UniversitatWien, Austria (2001) ISBN 3-9501031-1-2.16) P. Blaha, K. Schwarz, F. Tran, R. Laskowski, G. K. H.Madsen and L. D. Marks, J. Chem. Phys. 152, 74101(2020).17) C. Ambrosch-Draxl and J. Sofo, Comput. Phys. Com-mun. 175, 1 (2006).18) Y. Obukuro, K. Ninomiya, M. Arai, Y. Okuyama, G.Sakai and S. Matsushima, Comp. Mater. Sci. 126, 7(2017).19) G. I. Csonka, J. P. Perdew, A. Ruzsinszky, P. H. T.Philipsen, S. Lebègue, J. Paier, O. A. Vydrov and J. G.Ángyán, Phys. Rev. B 79, 155107 (2009).20) W. Setyawan and S. Curtarolo, Comp. Mater. Sci. 49,299 (2010).21) R. O. Jones and O. Gunnarsson, Rev. Mod. Phys. 61,689 (1989).22) P. Mori-Sánchez, A. J. Cohen and W. T. Yang, Phys.Rev. Lett. 100, 146401 (2008).23) J. Wiktor, I. Reshetnyak, F. Ambrosio and A.Pasquarello, Phys. Rev. Mater. 1, 022401(R) (2017).24) T. D. H. Nguyen, V. K. Dien, H. D. Pham, T. M. D.Huynh and M.-F. Lin, Comp. Mater. Sci. 198, 110675(2021).Kojima et al.: First-principles study on electronic structure and optical properties of Mn-doped Ba3V2O8JCS-Japan310