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To disseminate, educate, and validate psychiatric clinical practice guidelines, the Effectiveness of Guidelines for Dissemination and Education in Psychiatric Treatment (EGUIDE) project was launched in 2016. In this study, we investigated whether the web-based courses offered by this project would be as effective as the face-to-face courses. We analyzed and compared survey answers about overall participant satisfaction with the course and answers regarding clinical knowledge of schizophrenia and major depressive disorder between 170 participants who took the web-based courses in 2020 and 689 participants who took the face-to-face courses from 2016 to 2019. The web-based course participants completed the survey questions about satisfaction with the web-based courses. The web-based courses were conducted using a combination of web services to make it as similar as possible to the face-to-face courses. The degree of satisfaction assessed by the general evaluation of the web-based courses was higher than what was expected from the face-to-face courses. The degree of satisfaction was similar for the courses on schizophrenia and major depressive disorder. In addition, there were no significant differences in overall satisfaction and clinical knowledge between web-based and face-to-face courses. In conclusion, the web-based courses on clinical practice guidelines provided by the EGUIDE project were rated as more satisfying than the face-to-face course that the participants expected to take and no differences in the effectiveness of either course. The results suggest that, after the COVID-19 pandemic, it would be possible to disseminate this educational material more widely by adopting web-based courses additionally face-to-face courses.

The crystals of Mn4+-activated fluorides, such as those of the hexafluorometallate family, are widely known for their luminescence properties. The most commonly reported red phosphors are A2XF6: Mn4+ and BXF6: Mn4+ fluorides, where A represents alkali metal ions such as Li, Na, K, Rb, Cs; X=Ti, Si, Ge, Zr, Sn, B = Ba and Zn; and X = Si, Ge, Zr, Sn, and Ti. Their performance is heavily influenced by the local structure around dopant ions. Many well-known research organizations have focused their attention on this area in recent years. However, there has been no report on the effect of local structural symmetrization on the luminescence properties of red phosphors. The purpose of this research was to investigate the effect of local structural symmetrization on the polytypes of K2XF6 crystals, namely Oh-K2MnF6, C3v-K2MnF6, Oh-K2SiF6, C3v-K2SiF6, D3d-K2GeF6, and C3v-K2GeF6. These crystal formations yielded seven-atom model clusters. Discrete Variational Xα (DV-Xα) and Discrete Variational Multi Electron (DVME) were the first principles methods used to compute the Molecular orbital energies, multiplet energy levels, and Coulomb integrals of these compounds. The multiplet energies of Mn4+ doped K2XF6 crystals were qualitatively reproduced by taking lattice relaxation, Configuration Dependent Correction (CDC), and Correlation Correction (CC) into account. The 4A2g→4T2g (4F) and 4A2g→4T1g (4F) energies increased when the Mn-F bond length decreased, but the 2Eg → 4A2g energy decreased. Because of the low symmetry, the magnitude of the Coulomb integral became smaller. As a result, the decreasing trend in the R-line energy could be attributed to a decreased electron–electron repulsion.

Background Polypharmacy of additional psychotropics alongside the main treatment drug (antipsychotics in schizophrenia and antidepressants in major depressive disorder) is common in Japan. Our goal is to align psychotropic prescription in Japan with international standards, while reducing the differences between facilities. To achieve this goal, we aimed to compare prescriptions at the time of hospital admission and discharge. Methods Data on prescriptions at admission and discharge from 2016 to 2020 were collected. We divided the patients into four groups: 1) mono_mono group, monotherapy of the main drug at admission and discharge; 2) mono_poly group, monotherapy at admission and polypharmacy at discharge; 3) poly_poly group, polypharmacy at admission and discharge; and 4) poly_mono group, polypharmacy at admission and monotherapy at discharge. We compared the changes in dosage and number of psychotropics among the four groups. Results For both schizophrenia and major depressive disorder, the patients who received monotherapy with the main drug at admission were likely to receive main drug monotherapy at discharge and vice versa. For schizophrenia, the polypharmacy was prescribed more often in the mono_poly group than that in the mono_mono group. The prescription was not changed at all for more than 10% of the patients. Conclusions It is critical to avoid a polypharmacy regimen to ensure that guideline-compliant treatment is provided. We expect higher rates of monotherapy with the main drug after the EGUIDE lectures. Trial registration:The study protocol was registered in the University Hospital Medical Information Network Registry(UMIN000022645).

We investigated the association of electroconvulsive therapy (ECT) with anxiolytic and sleep medication use in patients with major depressive disorder (MDD) and schizophrenia (SZ).This nationwide observational study analyzed data from 3483 MDD inpatients and 6663 SZ inpatients. Patients with MDD and SZ were classified into those who underwent ECT during hospitalization and those who did not. A propensity score-matching method was performed to adjust for preadmission characteristics and clinical information, which were expected bias between the two groups. Rates of anxiolytic and sleep medication use at discharge were compared in the matched sample.500 MDD patients were assigned to both groups. In the matched MDD sample, the rate of anxiolytic and sleep medication use at discharge was significantly lower in the ECT group than in the non-ECT group (64.9% vs. 75.8%, P = 1.7 × 10Reduction of anxiolytic and sleep medication use may be considered positively when ECT is indicated for treatment of MDD.

Purpose: In the treatment guidelines for major depressive disorder (MDD), the recommended treatment differs based on the severity. However, the type of treatment provided based on the severity of MDD in real-world clinical practice has not been investigated. In this study, we clarified the actual situation of MDD treatment in clinical practice and compared the treatment based on the severity of MDD. Methods: We used data from 1484 patients with MDD at discharge from October 2016 to March 2020. Results: The number of psychotropic prescriptions tended to be lower in those diagnosed with MDD in the severe group compared to in the non-severe group. There were significant differences among the three groups (mild, moderate/severe, and psychotic) in the percentage of patients who were not prescribed antipsychotics (p = 1.9 ×10-6), a combination of antipsychotics and antidepressants (p = 5.0 ×10-4), and the implementation rate of modified electroconvulsive therapy (m-ECT) (p = 3.4 ×10-9). The percentage of patients with a severe diagnosis who underwent m-ECT was higher, which corresponded to the severity. Conclusion: Our findings showed that the use of psychotropics decreased when the severity of MDD was diagnosed, and the rate of a combination of antipsychotics and antidepressants and the implementation rate of m-ECT increased with the severity. However, this study suggests that there is still an evidence-practice gap in the treatment of MDD in Japan, and guidelines are only partially adhered to in the treatment of depression.

[Study objectives] To investigate the proportion of inpatients with schizophrenia and major depressive disorder prescribed hypnotic medication, and the association between such medication and the use of other antipsychotic agents. [Methods] This was a nationwide cross-sectional study performed as part of the ‘Effectiveness of Guidelines for Dissemination and Education in Psychiatric Treatment’ (EGUIDE) project. Data from 2146 inpatients with schizophrenia and 1031 inpatients with major depressive disorder were analyzed. All types and dosages of psychotropic drugs were recorded and the data at the time of discharge were analyzed. Associations between the use of hypnotic medication and other antipsychotic agents were evaluated using multivariate logistic regression analyses. [Results] The proportions of schizophrenia patients who were prescribed any and two or more hypnotic agents were 55.7% and 17.6%, respectively, and the corresponding proportions for patients with major depressive disorder were 63.6% and 22.6%, respectively. In schizophrenia patients, multivariate logistic regression analyses showed that two or more antipsychotics, anticholinergic drugs, anxiolytics, and mood stabilizers/antiepileptic drugs were positively associated with the use of any hypnotic agent. In patients with major depressive disorder, multivariate logistic regression analyses revealed that two or more antidepressants, two or more antipsychotics, anxiolytics, and mood stabilizers/antiepileptic drugs were positively associated with the use of any hypnotic agent. [Conclusions] Prescription of hypnotic agents was found to be highly frequent among inpatients with psychiatric disorders. Prescription of two or more main antipsychotic agents was commonly associated with the use of hypnotic medication for both schizophrenia and major depressive disorder.

In order to establish a method to predict the 4f 7 -4f 6 5d 1 transition energy of Eu 2+ in oxides, linear regression models were created based on first-principles calculations and machine learning. The model clusters consisting of the central Eu 2+ and O 2- ions closer than the nearest cation were constructed and the 4f 7 -4f 6 5d 1 absorption energy of Eu 2+ in these clusters were calculated by first-principles many-electron calculation using the relativistic discrete variational multi-electron (DVME) method. However, the 4f 7 -4f 6 5d 1 absorption energies of Eu 2+ in oxides calculated by relatively simple first-principles calculations tend to be overestimated by ca. 1.6 eV. In order to improve the accuracy of the prediction, we performed machine learning considering the calculated absorption energy as well as the other electronic and structural parameters as the attributes. As a result, the regression formula to predict the 4f 7 -4f 6 5d 1 absorption energy of Eu 2+ in oxides has been created by machine learning. The 4f 7 -4f 6 5d 1 absorption energy predicted by this model are in good agreement with the experimental ones. Therefore, accuracy of the prediction was significantly improved compared to the simple first-principles calculations. In a similar way, a predictive model of the 4f 6 5d 1 -4f 7 emission energy of Eu 2+ in oxides has been also created

Background Guideline for Pharmacological Therapy for Schizophrenia was published by the Japanese Society of Neuropsychopharmacology in 2015. “Effectiveness of Guidelines for Dissemination and Education in psychiatric treatment (EGUIDE)” project aimed to standardize medical practice using quality indicators (QIs) as indices to evaluate the quality of medical practice. In this study, we have reported the quality indicator values of prescription before the beginning of the guideline lectures in the EGUIDE project to ascertain the baseline status of treating patients with schizophrenia. Methods A cross‐sectional, retrospective case record survey was conducted, involving 1164 patients with schizophrenia at the time of discharge. We checked all types and dosage of psychotropic drugs. Results Forty‐three percent of patients had antipsychotic polypharmacy, and substantial concomitant medication was observed (antidepressants; 8%, mood stabilizers: 37%, anxiolytics or hypnotics: 68%). Conclusions In the results obtained in this study, we plant to report changes in the effectiveness of education in the EGUIDE project near the future., This study reports the prescription pattern in schizophrenia in Japan from EGUIDE (Effectiveness of Guideline for Dissemination and Education in psychiatric treatment) project. A cross‐sectional, case record survey conducted, involving 1164 patients with schizophrenia at the time of discharge. Forty‐three percent of patients received antipsychotic polypharmacy. Based on the results, we plan to report changes in the effectiveness of education in the EGUIDE project in the future.

To review the recommendations for the production of novel red phosphor materials, in this work we established the multiplet energy diagram of Mn4+ in a-Al2O3 under pressure. By the discrete variational multi-electron (DVME), the calculations were conducted based on many-electron approaches. Since the experimental data of Mn4+ in a-Al2O3 at zero pressure was the only data reported so far, the results in this work are our predictions. The effect of increasing pressure is naturally similar with the effect of decreasing bond length. This work indicates that the multiplet energies responsible for the absorption process increase as the pressure increase. Whereas, those responsible for the emission process decrease. These tendencies are the same as our previous calculations on a-Al2O3: Cr3+.

The fifth edition of the Diagnostic and Statistical Manual of Mental Disorders (DSM-5) was published in 2013, and its official Japanese version was published in 2014. The Japanese Government uses classifications from the 10th revision of the I nternational C lassification of D iseases (ICD-10) to categorize disorders and determine treatment fees. However, since the publication of the DSM-III, the use of the DSM system has become prevalent in research and educational settings in Japan. In addition to traditional psychiatry, both the ICD and the DSM are taught by many Japanese medical schools, and virtually all clinical research and trials refer to the DSM to define targeted disorders. Amid the current backdrop in which the reputation of the DSM-5 is being established, the editorial board of P sychiatry and C linical N eurosciences has asked Japanese experts across 12 specialties to examine the structure of the DSM-5, including the following categories: Neurodevelopmental Disorders, Schizophrenia Spectrum Disorders, Major Depression, Bipolar Disorders, Obsessive-Compulsive Disorders, Somatic Symptom Disorder, Eating Disorders, Substance-Related and Addictive Disorders, Gender Dysphoria, and Neurocognitive Disorders. Although opinions were only obtained from these selected experts, we believe that we have succeeded, to a certain extent, in presenting views that are representative of each specialty.

Metal complex indicates the significant physical properties such as magnetism, electrical conductivity and an optical property due to the electronic interaction between the ligand molecule and the central metal ion. We have evaluated the magnetism of the metal complex by controlling the ligand field splitting, which is the energy splitting of the d-orbitals. The magnetic phenomenon of such compounds are realized as a result of the electronic state based on the transition metal coordination complexes, and which can be switched between high spin (HS) and low spin (LS), that is called a spin-crossover (SCO) phenomenon. Our group have been investigated the way how to control the spin state according to the concept of a molecular distortion. The five-coordinated metal complex ML5 has been experimentally confirmed to be a molecular distortion called the Berry pseudorotation (BPR). In the BPR process, both the axial and equatorial ligands can move at the same rate of increasing the angle between the other axial or equatorial ligands in five-coordinated metal complex. The classical BPR mechanism changes its molecular symmetry between two independent trigonal bipyramidals (TBPs) of D3h symmetry via a square pyramidal (SP) of C4v symmetry. The distortion parameters in the five-coordinated metal complexes τ5 are proposed in order to represent the distortion of the BPR process quantitatively. In this work, we predicted the possibility of the SCO phenomenon in intramolecular exchange mechanism through the BPR process in a five-coordinated metal complexes.

Corundum can contain various transition metals as impurities, for example, ruby. Ruby is used as solid state laser. The prediction of the electronic state of these transition metals is very important for the development of novel optical materials. The CI calculation used finite Slater determinants, the calculated mutiplet energies is overestimated generally. In this study, we optimized the calculation multiplet energy of transition metals in α-Al2O3 by considering some corrections.

The first-principles calculations of the energies of the emission level (2Eg) of Cr3+ in 10 oxide crystals were performed using the first-principles configuration-interaction calculations. In order to improve the accuracy of the prediction, a machine learning model was created by using the results of the first-principles calculations and the experimental 2Eg energies as the training data. The predicted values using this model showed good correlation with the experimental values, where the correlation coefficient is 0.92. The obtained predicted model indicated that the Cr 3d component of t2g molecular orbital is the most important quantity for prediction of the 2Eg energy.

Search of new luminescence materials to improve the current white-ight emitting diode (LED) is still ongoing. Several investigations such as the ion dependence, the host crystal dependence has been done previously. Since we want to get a complete picture of ion-host combination dependence, we investigated α-Al2O3: TM3+. In this work we estimated the optical properties of α-Al2O3 doped with Co3+. We constructed model clusters consisting of 7 atoms. The lattice relaxation effects due to the Co3+ substitution were calculated using Shannon’s crystal radii method and geometry optimizations in the Cambridge Serial Total Energy Package (CASTEP) method. The one-electron Discrete Variational-Xα (DV-Xα) method was used to estimate the molecular orbital energies, while the many-electron Discrete Variational Multielectron (DVME) method was used to estimate the d-d absorption spectra. Since Co3+ belongs to 3d 6 configuration, there are two possible spin states i.e., high-spin (HS) and low-spin (LS) states.

Because of the chiral nature of the building blocks of living matter, an optical phenomena associated with the chirality constitute an important topic in physical chemistry. The specific optical rotation, which is a parameter for the characterization of the natural optical activity, depends strongly on the conformation of the molecule. In this study, we investigated the dependence of the optical rotation on a molecular conformation in the gas phase by calculating the electronic states of seven kind of chiral amino acids using the DV-Xα method. As a result, we can confirm the existence of an antibonding orbital on the side chain and the optical rotations are strongly related.

Up to recently, it has been difficult to calculate the multiplet energies of compounds using one-electron approach. Since it only considers one electron and one nuclei, the interaction among the electrons are neglected. Previously we have successfully estimated the 2E→ 4A2 (R-line) levels of ruby at 0 pressure using one-electron approach based on one-electron calculation using the first-principles Discrete Variational-Xα (DV-Xα) method. Here we want to perform similar investigation, not only for 0 pressure but up to 110 GPa. We estimated the lattice relaxation effect due to the Cr3+ substitution and due to the applied pressure by using two different methods i.e., Shannon’s crystal radii and geometry optimizations. Two different types of model cluster consisting of 7 and 63 atoms will be used. The 2E level is estimated by the barycenter of t2g 3 configuration which consists of 4 multiplets.

The 4f2−4f15d1 transition energy of Pr3+ in fluorides are utilized for various optical materials such as solid-state lasers, phosphors, and scintillators. Therefore, it is important to predict such energies of unknown materials for theoretical design of novel optical materials. In this study, we tried to predict the 4f2−4f15d1 transition energies of Pr3+ in fluorides based on first-principles calculations and machine learning. The first-principles calculations were performed based on the relativistic discrete variational multi-electron (DVME) method using the model clusters composed of the central Pr3+ and the anions closer than the nearest cation. Although the calculated 4f2−4f15d1 transition energies of Pr3+ in fluorides showed a relatively good correlation with the experimental ones, the calculated values tend to be overestimated by ca. 2 eV. In order to improve the accuracy of the prediction, we used the calculated transition energies as an attribute for machine learning. As a result, the regression formula to predict the 4f2−4f15d1 transition energy of Pr3+ in fluorides has been derived by machine learning using the calculated 4f2−4f15d1 transition energy as well as some other electronic and structural parameters as the attributes. The accuracy of the prediction was significantly improved compared to the simple first-principles calculations.

The discrete variational multi-electron (DVME) method is a first-principles many-electron calculation method based on the discrete-variational Xα (DV-Xα) molecular orbital method. There is also the relativistic version of the DVME method, which is based on the relativistic DV-Xα method. Since the explicit many-electron wave functions of the multiplet states of transition-metal (TM) or rare-earth (RE) ions in crystals can be obtained, the DVME method has been applied to the analyses of various luminescent materials such as solid-state lasers and phosphors. In this paper, as examples of the recent applications of the DVME method, the following researches will be briefly presented: (1) Visualization of the energy-structure relationship of Cr3+ in oxides, and (2) Creation of the predictive model of the multiplet energy using machine learning.

In order to calculate the LMCT energies for various trivalent TM ions in α-Al2O3 using realistic model clusters, we performed structural optimization using the CASTEP code and constructed the optimized TMO6 9- and TMAl13O6 30+ clusters (TM = Sc3+, Ti3+, V3+, Cr3+, Mn3+, Fe3+). We obtained the LMCT energies of TM ions by first-principles many-electron calculations using the DVME method. It was found that the differences between the LMCT energies of the optimized clusters and those of the relaxed clusters based on the crystal radii originate from the difference in the multiplet splitting of the LMCT states. The results also indicated that the LMCT energies of transition metal ions in α-Al2O3 can be calculated using small clusters composed of the central TM ion and the first-neighbor oxygen ions.

Due to its potential application in luminescence technologies, the complete understanding on pressure dependence of ruby is especially important. Up to recently, the theoretical prediction on the structural properties of ruby under pressure has been made involving the empirical parameters. Therefore, here we performed a non-empirical study on the pressure dependence of ruby bond length. Due to the Cr3+ substitution and the applied external pressure, the local structure of α-Al2O3: Cr3+ was changed. We estimated this effect by performing the first-principles band-structure calculations using Cambridge Serial Total Energy Package (CASTEP) method and compared with the Shannon’s crystal radii method. The two different bond lengths; Cr-1st nearest neighbour oxygen (d 1) and Cr-2nd nearest neighbour oxygen (d 2) were investigated in detail. The results show that under 0-110 GPa the d 1 and d 2 decreased ca. 0.172 and 0.145 Å, respectively. These results were slightly smaller than the d 1 and d 2 decreases in the case of pure α-Al2O3 crystal, they were observed to be ca. 0.167 Å for d 1 and 0.177 Å for d 2. In the other words, the d 1-d 2 differences were larger at the higher pressure, ca. 0.052-0.080 Å for 0-110 GPa.

The Y3Al5−xGaxO12(YAGG):Ce3+-Cr3+ persistent phosphor is one of the materials in which Cr3+ ions act as electron traps. The possibility of electron traps by other transition metal ions (TM3+, TM = Sc, Ti, V, Cr, Fe) was investigated and those electron trap depth was compared with each other. In the thermoluminescence (TL) glow curves, the YAGG:Ce3+ samples co-doped with different TM3+ ions show different TL glow peak temperatures (i.e. different electron trap depth). The estimated vacuum referred binding energy of TM2+ from the trap depth shows a zig-zag curve, which is found to be originated from the different 3d electron energies affected by a number of d electron, nuclear charge and crystal field splitting. Utilizing the obtained TM2+ zig-zag curve, a new persistent phosphor of Y3Al2Ga3O12:Ce3+-Sc3+ and a photostimulated phosphor of Y3Al2Ga3O12:Ce3+-V3+ were successfully developed.

We carried out a comparative study on R-line and U-band energies of α-Al2O3: Cr3+ material, or the so-called ruby, estimated from one-electron and many-electron first-principles calculations. The estimations were performed without relating to any observed parameter. Although there are numerous reports on the ab-initio calculations of absorption spectra and multiplet energies of ruby based on many-electron approach, the investigation based on one-electron approach is basically impossible except for some particular states such as 4T2 and 2E. Here we compared the transition energies from the 4A2 state (ground state) to 4T2 state (U-band) and to 2E (R-line) of ruby estimated by one-electron and many-electron first-principles approaches. The one-electron calculations were carried out utilizing using discrete variational Χα (DV-Χα) method combined with ligand field theory, while the many-electron calculations were carried out utilizing using the discrete variational multi-electron (DVME) method. The results show that generally both of the one-electron and the many-electron first-principles calculations can be utilized to estimate the multiplet energies such as U-band and R-line energies. Nevertheless, the refined formula to estimate the R-line energy based on one-electron approach is necessary to enhance the concurrence with the observed data.

The fifth edition of the Diagnostic and Statistical Manual of Mental Disorders (DSM-5) was published in 2013, and its official Japanese version was published in 2014. The Japanese Government uses classifications from the 10th revision of the I nternational C lassification of D iseases (ICD-10) to categorize disorders and determine treatment fees. However, since the publication of the DSM-III, the use of the DSM system has become prevalent in research and educational settings in Japan. In addition to traditional psychiatry, both the ICD and the DSM are taught by many Japanese medical schools, and virtually all clinical research and trials refer to the DSM to define targeted disorders. Amid the current backdrop in which the reputation of the DSM-5 is being established, the editorial board of P sychiatry and C linical N eurosciences has asked Japanese experts across 12 specialties to examine the structure of the DSM-5, including the following categories: Neurodevelopmental Disorders, Schizophrenia Spectrum Disorders, Major Depression, Bipolar Disorders, Obsessive-Compulsive Disorders, Somatic Symptom Disorder, Eating Disorders, Substance-Related and Addictive Disorders, Gender Dysphoria, and Neurocognitive Disorders. Although opinions were only obtained from these selected experts, we believe that we have succeeded, to a certain extent, in presenting views that are representative of each specialty.

In this study, we performed an investigation on α-Al2O3: V3+ material, or the so-called color change sapphire, based on first-principles calculations without referring to any experimental parameter. The molecular orbital (MO) structure was estimated by the one-electron MO calculations using the discrete variational-Xα (DV-Xα) method. Next, the absorption spectra were estimated by the many-electron calculations using the discrete variational multi-electron (DVME) method. The effect of lattice relaxation on the crystal structures was estimated based on the first-principles band structure calculations. We performed geometry optimizations on the pure α-Al2O3 and with the impurity V3+ ion using Cambridge Serial Total Energy Package (CASTEP) code. The effect of energy corrections such as configuration dependence correction and correlation correction was also investigated in detail. The results revealed that the structural change on the α-Al2O3: V3+ resulted from the geometry optimization improved the calculated absorption spectra. By a combination of both the lattice relaxation-effect and the energy correction-effect improve the agreement to the experiment fact.

Recently, fluorescence spectra of rare-earth ions in oxide materials are very attractive for the applications of the optical amplification in optical fiber communications, white LED, etc. However, it has been difficult to calculate the fluorescence spectra of rare-earth ions by the first principle method. In this study, we used the relativistic discrete-variational multielectron (DVME) method, which is a configuration-interaction (CI) calculation program using the molecular orbitals obtained by the relativistic DV-Xα method. We applied this method for the calculation of the fluorescence spectrum of the Pr3+ ions in phosphate materials. The transition probability of the fluorescence was calculated in the same manner of the absorption. The obtained theoretical fluorescence spectrum was in good agreement with the experimental one, though the intensity of each peak was deeply dependent on the configuration of the surrounding structural units. The results suggested that the DVME method was useful for the calculation of not only absorption but also fluorescence spectra of rare-earth ions in oxide materials. © 2009 Wiley Periodicals, Inc. Int J Quantum Chem, 2009

In this paper, we investigated the 4f–5d transition energy of Ce3+ in various fluoride hosts based on the first-principles discrete-variational Dirac–Slater (DV-DS) calculations using Slater's transition-state theory. Especially, we focused on the lowest energy peak (1st peak) of 4f–5d transition for Ce3+ impurities. As the host crystals, we adopted the 15 fluorides, for which the experimental data of the lowest energy peak (1st peak) in 4f–5d transitions were available from literature except for NaMgF3 and BaMgF4. A high correlation between the experimental 1st peak energies and the theoretical ones was obtained which suggests a possibility to predict the 4f–5d transition energy of Ce3+ in various fluoride hosts using the first-principles calculation.

Systematic calculations of multiplet energy levels of all trivalent lanthanides in LiYF{sub 4} (YLF) crystal were performed using two completely different approaches: diagonalization of the commonly used semi-empirical Hamiltonian and a fully relativistic discrete-variational multi-electron (DV-ME) method which is based on a first-principles configuration-interaction (CI) calculation program using molecular spinors obtained by the discrete-variational Dirac-Slater (DV-DS) calculations. The energy level diagrams within 4f{sup n} electron configurations were obtained by the former method, while those including both 4f{sup n} and 4f{sup n-1}5d{sup 1} configurations were obtained by the latter. Using the explicit many-electron wave functions, the absorption spectra of Pr{sup 3+}, Ho{sup 3+}, and Tm{sup 3+} in YLF were calculated and compared with the experimental data.

A first-principles fully relativistic multielectron method based on molecular orbital (MO) theory is applied to the analysis for the 4f5d configurations of Pr 3+ -doped LaF 3 , LiYF 4 (YLF), and CaF 2 crystals. The formation of MOs between the Pr 5d orbitals and the ligand fluorine 2p orbitals is considered using a (PrF 11 ) 8− and (PrF 8 ) 5− molecular models. The energy of the lowest level of 4f5d configuration decreases in the order LaF 3 , LiYF 4 , and CaF 2 (O h symmetry). The high energy in Pr 3+ :LaF 3 is ascribed to the smaller ligand-field splitting due to the large coordination number. The analysis of many-electron wave functions shows the mixtures between the spin-orbit splitting of the 4f-level MOs and the ligand-field splitting of the 5d-level MOs. Configuration interaction with one-electron excitations gives transition probability to the originally forbidden two-electron excitations, which produce satellite structures in spectra.

A newly developed first-principles many-electron method which is based on molecular orbital (MO) theory is applied to the analysis of the 4f–5d transition of a (PrF 8 ) 5− cluster and the 5f–6d transition of a (UF 8 ) 4− cluster in LiYF 4 (YLF) crystal. Strong peaks in the f–d bands are mainly assigned to the transitions to the first three ligand–field components in the d levels. In principles, all peaks are interpreted by mixtures between various one-electron transitions. The larger spin–orbit splitting in the 5f levels in U 4+ :YLF leads to the assignment of peaks different from Pr 3+ :YLF.

X-ray absorption near edge structure (XANES) at L2;3-edge of 3d transition elements is dominated by strong correlation effects among 2p core hole and 3d electrons. In the present study, we have performed systematic configuration interaction (CI) calculations in order to reproduce and interpret Fe-L2;3 XANES of FeO, LaFeO3 and SrFeO3. Relativistic four components wave functions were obtained by solving Dirac equations with density functional theory. CI calculations were made using the relativistic molecular orbitals instead of atomic orbitals, which enables inclusion of the O-2p orbital contributions through covalency. The oscillator strength of the electric dipole transition was then computed.

First-principles relativistic configuration-interaction (CI) calculations of cation L2,3-edge electron-energy-loss near-edge structures (ELNES) of SrTiO3, NiO and CaF2 have been carried out based on the direct approach where the ground state (GS) configuration and the excited state (ES) configuration were calculated simultaneously by direct diagonalization of the many-electron Hamiltonian. The obtained theoretical spectra were compared with our recent results based on the indirect approach where the GS configuration and the ES configuration were calculated separately and their energy separation was adjusted to the value predicted by the Slater’s transition-state calculation. Although both approaches well reproduced the overall features of the experimental spectra, the direct approach tend to slightly overestimate the absolute transition energies. In the case of Ti L2,3-edge of SrTiO3, however, the absolute transition energies calculated by the direct approach were comparable to those by the indirect approach and were also in good agreement with experimental values, indicating sufficient inclusion of electron correlations through pure configuration interactions.

The multiplet structure of the tetrahedrally coordinated Cr4+ in Y3Al5O12 [yttrium aluminum garnet (YAG)] was calculated by the ab initio electronic-structure calculation method. The authors examined the dependence of the multiplet structures on the size of cluster models, with the use of (CrO4)4− (without point charges), (CrO4)4− (with point charges), (CrY6Al4O44)54−, and (CrY18Al42O148)112− models. The covalency of the impurity-level molecular orbitals was analyzed, and it was revealed that the wave functions of the atoms outside the CrO4 tetrahedron should not be neglected. The validity of the assignment of the peaks in the absorption spectrum written in the literature was evaluated by the calculated magnitude of the spin-orbit splittings and the oscillator strengths of the transitions, which were obtained by the fully relativistic many-electron calculation. The effect of the codopant on the transition probability was also estimated by (CrCaY5Al4O44)55− models. It was indicated that the nearest Cr–Ca pairs would reduce the symmetry, and could produce some satellite peaks. The mixing of the wave functions of the triplet states was numerically analyzed, and the results were correlated with the transition probability. The traditional nephelauxetic parameter was estimated, and the value 0.51 was obtained. It was confirmed from first principles that the magnitude of the nephelauxetic parameter in some literature was appropriate.