• Title/Summary/Keyword: crystal field theory

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Light-intensity Dependence of Diffraction Efficiency in - $Fe:LiNbO_3$ Crystals - (빔세기에 따른 $Fe:LiNbO_3$ 결정의 회절효율)

  • 정태혁
    • Korean Journal of Optics and Photonics
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    • v.4 no.3
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    • pp.323-329
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    • 1993
  • In this paper, dependence of the diffraction efficiency upon incident light intensity is studied. The conductivity ratio, which is dependent upon the incident light intensity, changes the static electric field in a crystal. This change of the static electric field modulates the refractive index via linear electro-optic effect. And the change of the refractive index affects the diffraction efficiency. It is found that experimental results with $Fe:LiNbO_3$ crystals are in good agreement with the theory.

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A Study of the Cubic Field Splitting Parameter 10Dq by Means of One-Center Expansion of Complex MO (착물 분자궤도함수의 일점 전개에 의한 입방결정장 분열 파라미터 10Dq의 고찰)

  • Hojing Kim;Sangyoub Lee
    • Journal of the Korean Chemical Society
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    • v.22 no.2
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    • pp.67-77
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    • 1978
  • MO's of a complex are expanded in terms of the set of Shull-Lowdin functions based on a single point, the nucleus of central metal ion, and the result was interpreted from the viewpoint of perturbation theory. We find that even in the case of $[NiF_6]^{4-}$, which has relatively small covalency, excited configurations with high orbital angular momentum are considerably mixed into $e_g$ and $t_{2g}$, orbitals of central metal ion, and that the distortions in these orbitals differ from each other. Therefore it is concluded that the energy difference between $e^*_g$ and $t^*_{2g}$, orbitals evaluated in the MO scheme has little meaning of the unique parameter 10Dq in the crystal field theory, and that such a unique parameter cannot be defined in a rigorous sense in the MO scheme.

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A Study on the Magnetic Properties of Polycrystailine${(Fe,In,Eu)}_2O_3$ (다결정${(Fe,In,Eu)}_2O_3$계의 자기적 성질에 관한 연구)

  • 김정기;서정철;한은주;홍양기
    • Journal of the Korean Magnetics Society
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    • v.1 no.1
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    • pp.1-5
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    • 1991
  • The magnetic properties of the polycrystalline ${(Fe_{2}O_{3})}_{1-x-y}{(In_{2}O_{3})}_{x}{(Eu_{2}O_{3})}_{y}$(x=0.01, y=0.02과 x=0.02, y=0.03) have been studied by the methods of X-ray diffraction, $M\"{o}ssbauer$ effect, and magnetic hysteresis measurement. The X-ray diffraction patterns show that the samples have a same crystal structure as $\alpha-Fe_{2}O_{3}$. From the analysis of the temperature dependence of the quadrupole splitting and average half-width, it is found that the Morin transition occurs in the sample of x=0.01 and y=0.02 and the spin angle defined as the angle between the [111] crystal axis and antiferromagnetic vector, changes from about $35^{\circ}$ to the (111) plane as increasing the temperature in the sample of x=0.02 and y=O.03. The temperature dependence of magnetic hyperfine field is analyzed by using the spin-wave theory. The isomer shift values at room temperature are found to be given by about 0.35mm/s for the samples which means that the Fe ions belong to $3^{+}ion$. The temperature dependence of isomer shift was analyzed by using the Debye model.

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Intracavity frequency doubling of a single-mode Nd:YAG laser using a nonplanar ring cavity (비평면 고리형 공진기를 이용한 단일 모드 Nd:YAG 레이저의 내부 공진기 주파수 배가)

  • 박종락;윤태현
    • Korean Journal of Optics and Photonics
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    • v.14 no.1
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    • pp.85-91
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    • 2003
  • Intracavity frequency doubling of a single-mode Nd:YAG laser by using a nonplanar ring cavity is demonstrated. The nonplanar ring cavity consists of a Brewster-angled Nd:YAG crystal placed in a magnetic field, a KTP crystal, and two spherical mirrors. In this design the Nd:YAG block acts as both a nonreciprocal polarization rotator and a partial polarizer, and the nonplanar portion of the ring cavity, which is formed by a relative twist angle between the Brewster-angled end surfaces of the Nd:YAG block, serves as a reciprocal polarization rotator. An eigenpolarization theory for the cavity configuration is presented and suitable values of the relative twist angle for unidirectional operation are estimated. A single-mode output power of 22 ㎽ at 532 nm and an optical to optical conversion efficiency of 1.8% are obtained with a 1.2 W diode laser at 809 nm.

The Effect of Ligand's Spin-Orbit Coupling and the Intermixing of │3d 〉 and │4p 〉 Cu Atomic Orbitals on Zero-Field Splitting in the Tetragonally Distorted Tetrahedral $CuCl_4^{2-}\;Complex^\ast$ (Cu 3d 와 4p 궤도함수의 혼성과 리간드의 Spin-Orbit Coupling 이 Tetragonally 일그러진 $CuCl_4^{2-}$ 착물의 Zero-Field Splitting에 미치는 영향)

  • Lee, Wang No;Choe, U Seong;Baek, U Hyeon;Kim, Dong Hui;Choe, Chang Jin;Lee, Gi Gye
    • Journal of the Korean Chemical Society
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    • v.34 no.1
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    • pp.37-43
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    • 1990
  • An effect of the spin-orbit coupling interaction of ligand orbitals and the intermixing │3d 〉and│4p > transition metal atomic orbitals on the ground state for a 3$d^9$ system in a strong crystal field of tetragonally distorted tetrahedral symmetry that belongs to the $D_{2d}$ point group has been investigated in this work, applying the degenerate perturbation theory. An LCAO-MO analysis in terms of the known energies of the d-d transitions for the tetragonally distorted $CuCl_4^{2-}$ ion in a single crystal of$Cs_2CuCl_4$shows that the covalent mixing of Cu 3d and ligand Cl 3p orbitals decreases dramatically with increasing Cu 4p contribution. The extent of effect on the energy level splitting for the ground state by the spin-orbit coupling interaction of ligand orbitals decreases significantly in orderTEX>$\Gamma_7(E)\;\to\;\Gamma_6(E)\; >\;\Gamma_7(B_2)\;\to\;\Gamma_6(E)\; >\;\Gamma_7(B_2)\;\to\;\Gamma_7(E)$.

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Adsorption Characteristics of Heavy Metals in Wastewater on Bone Charcoal (Bone Charcoal에 의한 폐수증의 중금속 흡착특성)

  • Chung, Paul-Gene;Kwak, Dong-Heui;Lee, Jae-Wook
    • Journal of Korean Society on Water Environment
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    • v.16 no.4
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    • pp.555-563
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    • 2000
  • The study was conducted to evaluate the adsorption equilibrium of heavy metals on bone charcoal made of livestock bone which was sintered at $550{\sim}600^{\circ}C$. Analysis of bone charcoal by XRD and FT-IR showed that crystal structure was similar to that of synthetic hydroxyapatite. Adsorption equilibrium capacity of single component (Pb, Cd, and Zn) on bone charcoal could be expressed as Langmuir, Freundlich, and Sips equations. Sips isotherm was best among the three isotherms. The values predicted by IAST(ideal adsorbed solution theory) showed good relationship to the experimental data in multicomponent adsorption equilibrium. Adsorption affinity was in order of Pb, Cd, and Zn. The order was same in case of activated carbon or synthetic hydroxyapatite. Through the study results. it would be expected that bone charcoal made of livestock could be used in field of wastewater treatment plants as adsorbent to remove heavy metal.

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Pattern Recognition using Two-Pupil Optical Scanning Technique and PAL-Spatial Light Modulator (Two-pupil 광학 스캐닝 기술과 PAL-공간변조기를 이용한 패턴 인식)

  • Doh, Kyu-Bong;Kim, Kwan-In;Kim, Myeong-Soo
    • Journal of Advanced Navigation Technology
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    • v.12 no.6
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    • pp.659-665
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    • 2008
  • We demonstrate experimentally that the method of Two-pupil optical scanning technique with PAL-spatial light modulator is capable of performing real-time joint transform correlation(JTC) optical system. Optical addressing is achieved by the use of a photosensitive layer of $\alpha$ - Si which controls the electric field across the liquid crystal The demonstrated technique is based on two-pupil optical heterodyne scanning. The method is independent of a spatial light modulator (SLM) in the Fourier plane. We develop the theory of the technique and evaluate a performance of the method by experimentally estimating the correlation between the target image and the reference image.

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Color therapy and application of color to oriental medical science (색채치료(色彩治療)와 한의학(漢醫學)에서의 색(色)의 적용(適用))

  • Park, Seung Lim;Kang, Jung Soo
    • Journal of Haehwa Medicine
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    • v.12 no.1
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    • pp.79-102
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    • 2003
  • It has been believed that the human body can be effected by color, sound, smell, and taste - each of them is based on the original character. Out of these elements, the color can be a mediation that absorbs energy into human body and adapts it to the creatures whose life are definitely based on the solar energy. This thesis makes a study of the possibility of applying the color to the oriental medical science by researching the color psychology and therapy which are studied in the west medical science, the recognition and application of color developed from orientalism, and the opinion of color in the oriental medical science. Color therapy is one of the psychological treatment techniques that are able to recover and maintain the health with the rays of the sun rays and the color. The light and the color have its energy that may relax, harmonize, encourage, or excite a human being. This is because the wavelength and the vibration of each color will take effects to human body. The core energy of absorbing and distributing the color vibration is made in the 7 "chakras" in the body, which are the pith and marrow of bio-energy directly connected with the center of the nervous system. There are several methods in the color therapy - the treatment of solar ray, the color-bath, the water-therapy using color energy, the inducement of the solar energy into the body, the acupuncture, the therapy of crystal and jewel, and the self-suggestion dependent upon the color. The color therapy can help us to keep our balance by changing the emotion into the positive energy that will cure the disease with color. As a result, this method not only must be useful to cure physical disease, or develop into good health but also will be used in conforming itself to the mental disease. The color therapy mainly uses the eight colors, which are made by mixing Red, Yellow and Blue basic colors in the field. They are never used in the treatment, but they will go along with complementary colors. This rule is closely connected with the theory of yin and yang which lies at the root of oriental philosophy, and with the treatment principle of oriental medical science whose field is focused on the balancing the body mentally as well as physically. In the East, it is the Obangsaek - the color of blue, red, yellow, white, and black in the theory of yin and yang and the five elements that have been used in helping people having trouble with their health for a long time. In the view of the oriental medical science, these five colors attached the theory of five-elements have been very useful to the physiology, the pathology, or the diagnosis, and been applied to the medical treatment, combining themselves with a five-taste in medicinal herbs. Since the study of color and human physiology has been made in some different interest and fields these days, it goes to prove that the different function of color we couldn't have got before becomes very useful to the medical science. The color must be worth researching the diversity for applying itself to the oriental medical science.

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Optical properties of $\beta$-$In_2S_3$ and $\beta$-$In_2S_3$:$Co^{2+}$ Thin Films

  • Kim, Hyung-Gon;Kim, Nam-Oh;Jin, Moon-Seog;Oh, Seok-Kyun;Kim, Wha-Tek
    • Transactions on Electrical and Electronic Materials
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    • v.2 no.1
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    • pp.27-31
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    • 2001
  • $\beta$-$In_2S_3$ and $\beta$-$In_2S_3$:$Co^{2+}$ thin films were grown using the spray pyrolysis method. The thin films crystallized into tetragonal structures. The indirect energy band gap of the thin films was found to be 2.32 eV for $\beta$-$In_2S_3$ and 1.81 eV for $\beta$-$In_2S_3$:$Co^{2+}$(Co:1.0 mol%) at 198K. The direct energy band gap was found to be 2.67 eV for $\beta$-$In_2S_3$ and 2.17 eV for $\beta$-$In_2S_3$:$Co^{2+}$(Co:1.0 mol%). Impurity optical absorption peaks were observed for the ${\beta}$-$In_2S_3$:$Co^{2+}$ thin films. These impurity absorption peaks are assigned, based on the crystal field theory, to the electron transitions between the energy levels of the $Co^{2+}$ ion sited in $T_{d}$ symmetry.

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Unidirectonal single-mode operation of a Nd:YAG laser by using a planar semimonolithic ring cavity (평면 반일체 고리형 공진기를 이용한 Nd:YAG 레이저의 단방향 단일 모드 발진)

  • 박종락;이해웅;윤태현;정명세
    • Korean Journal of Optics and Photonics
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    • v.10 no.4
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    • pp.311-317
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    • 1999
  • Unidirectional single-mode operation of a diode-pumped Nd:YAG laser with a planar semimonolithic ring cavity has been demostrated at 1064 nm. The semimonolithic cavity consists of a laser active medium placed in a magnetic field, a crystal quartz plate, and an output coupling mirror. They form an optical diode by acting each part as a Faraday rotator, a reciprocal polarization rotator and a partial polarizer, respectively. An eigenpolarization theory for the cavity configuration was presented and losses for the eigenmodes were calculated. A pump-limited single-mode output power of 155 mW and a slope efficiency of 17% were obtained when the laser was pumped by a 1.2 W, 809 nm diode-laser. A laser linewidth of less than 100 kHz is inferred from a beat note frequency spectrum between two identical laser systems and continous single-mode tuning range was more than 2 GHz.

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