• Title/Summary/Keyword: Core-valence correlation

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Test of a Multi-Reference Many-Body Perturbation Theory for the Description of Electron Correlations in four Valence Electron States of Transition Metal Atoms

  • Lee, Yoon-Sup;Sun, Ho-Sung;Freed, Karl F.;Hagstrom, S.
    • Bulletin of the Korean Chemical Society
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    • v.7 no.4
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    • pp.262-266
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    • 1986
  • A multi-reference many-body perturbation theory (MRMBPT) method is critically tested in second order by comparing with the corresponding configuration interaction (CI) calculations. Excitation energies of the four-valence-electron states of transition metal atoms and ions are used for the comparison. The agreement between the second order MRMBPT and CI calculations is very reasonable, confirming the reliability of the second order MRMBPT method. The reliability of calculations with the present second order MRMBPT method was only been inferred empirically in the past since most results have been gauged by the agreement with experiment and/or with other MRMBPT calculations based upon different sets of orbitals and configuration spaces. The present MRMBPT method appears to be an efficient ab initio multi-reference method for the calculation of electron correlation effects in atoms and molecules, and it is shown how MRMBPT can be used to estimate core-core and core-valence correlation effects which are often omitted in CI calculations because too many configurations and correlating electrons are involved.

Affective Representation and Consistency Across Individuals Responses to Affective Videos (정서 영상에 대한 정서표상 및 개인 간 반응 일관성)

  • Ahran Jo;Hyeonjung Kim;Jongwan Kim
    • Science of Emotion and Sensibility
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    • v.26 no.3
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    • pp.15-28
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    • 2023
  • This study examined the affective representation and response consistency among individuals using affective videos, a naturalistic stimulus inducing emotional experiences most similar to those in daily life. In this study, multidimensional scaling was conducted to investigate whether the various affective representations induced through video stimuli are located in the core affect dimensions. A cross-participant classification analysis was also performed to verify whether the video stimuli are well classified. Additionally, the newly developed intersubject correlation analysis was conducted to assess the consistency of affective representations across participant responses. Multidimensional scaling revealed that the video stimuli are represented well in the valence dimension, partially supporting Russell (1980)'s core affect theory. The classification results showed that affective conditions were successfully classified across participant responses. Moreover, the intersubject correlation analysis showed that the consistency of affective representations to video stimuli differed with respect to the condition. This study suggests that the affective representations and consistency of individual responses to affective videos varied across different affective conditions.

Ab initio MRCI+Q Investigations of Spectroscopic Properties of Several Low-lying Electronic States of S2+ Cation

  • Li, Rui;Zhai, Zhen;Zhang, Xiaomei;Liu, Tao;Jin, Mingxing;Xu, Haifeng;Yan, Bing
    • Bulletin of the Korean Chemical Society
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    • v.35 no.5
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    • pp.1397-1402
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    • 2014
  • The complete active space self-consist field method followed by the internally contracted multireference configuration interaction method has been used to compute the potential energy curves of $X^2\prod_g$, $a^4\prod_u$, $A^2\prod_u$, $b^4\sum_{g}^{-}$, and $B^2\sum_{g}^{-}$ states of $S{_2}^+$ cation with large correlation-consistent basis sets. Utilizing the potential energy curves computed with different basis sets, the spectroscopic parameters of these states were evaluated. Finally, the transition dipole moment and the Franck-Condon factors of the transition from $A^2\prod_u$ to $X^2\prod_g$ were evaluated. The radiative lifetime of $A^2\prod_u$ is calculated to be 887 ns, which is in good agreement with experimental value of $805{\pm}10$ ns.

Consistency between Individuals of Affective Responses for Multiple Modalities based on Behavioral and Physiological Data (행동 및 생리측정기반 개인 간 다중 감각정서 반응일치성)

  • Junhyuk Jang;Jongwan Kim
    • Science of Emotion and Sensibility
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    • v.26 no.1
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    • pp.43-54
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    • 2023
  • In this study, we assessed how participants represent various sensory stimuli experiences through behavioral ratings and physiological measurements. Utilizing intersubject correlation (ISC) analysis, we evaluated whether individuals' affective responses of dominance, arousal, and valence differed when stimuli of three modality conditions (auditory, visual, and haptic) were presented. ISC analyses were used to measure the similarities between one participant's responses and those of the others. To calculate the intersubject correlation, we divided the entire dataset into one subject and all other subject datasets and then correlated the two for all possible stimulus pair combinations. The results revealed that for dominance, ISCs of the visual modality condition were greater than the auditory modality condition, whereas, for arousal, the auditory condition was greater than the visual modality. Last, negative valence conditions had the greater consistency of the participants' reactions than positive conditions in each of the sensory modalities. When comparing modalities, greater ISCs were observed in haptic modality conditions than in visual and auditory modality conditions, regardless of the affective categories. We discussed three core affective representations of multiple modalities and proposed ISC analysis as a tool for examining differences in individuals' affective representations.

Study of the Valence and Rydberg States of a Lithium Dimer by the Multi-reference Configuration-interaction Method

  • Lee, Chun-Woo
    • Bulletin of the Korean Chemical Society
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    • v.35 no.5
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    • pp.1422-1432
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    • 2014
  • Convergent all-electron multi-reference configuration-interaction (MRCI) calculations are performed for a lithium dimer with Kaufmann's Rydberg basis functions. A comparison of the results of these calculations with those of the effective core potential/core polarization potential (ECP/CPP) method and experimental data reveals the deficiency of the all-electron ab initio method. The deficiency is related to the mere 51.9% attainment of electron correlation for the ground state. The percent attainment of electron correlation for the first excited state is slightly better than that for the ground state, preventing us from obtaining better agreements with experimental data by means of increasing the size of basis sets. The Kaufmann basis functions are then used with the ECP/CPP method to obtain the accurate convergent potential energy curves for the $^1\prod_u$ states correlated to Li(2p) + Li(2p) and Li(2s) + Li(n = 2, 3, 4). Quantum defect curves (QDCs) calculated for both the $X^2\sum_g$ and 1 $^2\prod_u$ states of the $Li{_2}^+$ ion and the Lu-Fano plot reveal a strong series-series interaction between the two $2snp{\pi}$ and $2pnp{\pi}$ Rydberg series. The QDCs are then used to resolve assignment problems in the literature. The reassignments, performed by Jedrzejewski-Szemek et al., of the dissociation product of the D $^1\prod$ state from (2s+3d) to (2s+3p) and that of the 6 $^1\prod_u$ from (2s+4d) to (2s+4p) are found to be incorrect. It may be more natural to assign their $2snp{\pi}$ Rydberg series as a $2snd{\pi}$ series. The state, assigned as 5p $^1\prod_u$ by Ross et al. and 4d $^1\prod$ by Jedrzejewski-Szemek et al., is assigned as the 7 $^1\prod_u$ state, correlated to the Li(2s) + Li(4f) limit.

XPS Study of Mn 2pp and 3s Satellite Structures of Heusler Alloys: NiMnSb, ppdMnSb, pptMnSb

  • Yang, See-Hun;Oh, Se-Jung;ppark, Je-Geun
    • Proceedings of the Korean Vacuum Society Conference
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    • 1994.02a
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    • pp.50-50
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    • 1994
  • Half-metallic Heusler alloys (NiMnSb, ppdMnSb, pptMnSb) have attracted much attention due to their unique electronic and magnetic structures. Sppin-ppolarized band structure calculation ppredicts metallic behavior for the majority sppin states and semiconductor behavior for the minority sppin states. We have studied the electronic structures of these half-metallic Heusler alloys by core-level pphotoemission sppectroscoppy of Mn 2pp and 3s XppS sppectra. We found large intensities of Mn 2pp satellites and 3s exchange spplitting comppared with other metal Mn-alloys. These satellite structure can be understood by applying Anderson imppurity model. This fact supports the calculated sppin pprojected ppartial density of states which suggests that the valence electrons be highly sppin ppolarized near Fermi level and that the electrons involved with charge-transfer be mainly minority sppin ones which have semiconducting band structure. The trend of charge transfer energies Δ from ligands (Sb 5pp) to Mn 3d, obtained from our model fitting, is consistent with that calculated from sppin pprojected ppartial density of state. Also the trend of d-d electron correlation energies U calculated from Mn Auger line L3 VV by Mg $K\alpha$ source is comppatible with that resulted from our model fitting. We fitted the Mn 3s curve in the same way as for insulating Mn comppounds by using the same pparameters calculated from Mn 2pp curve fitting exceppt for the Coulomb interaction energy Q between core hole and d-electrons. The 3s sppectra were analyzed by combing the charge transfer model and a simpple model taking into account the configuration mixing effect due to the intra-shell correlation. We found that the exchange interaction between 3s hole and 3d electrons is mainly respponsible for the satellite of Mn 3s sppectra. This is consistent with the neutron scattering data, which suggests local 3d magnetic moment. We find that the XppS analysis results of Mn 2pp and 3s satellite structures of half-metallic Heusler alloys are very similar to those of insulating transition metal comppounds.

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