• Bulletin of the Korean Chemical Society
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• v.24 no.11
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• pp.1671-1674
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• 2003

The effects of amine donors ($a:NH_2,\;b:NMe_2,\;c:NMePh,\;d:NPh_2$) and conjugation length on the molecular hyperpolarizabilities of a series of dipolar molecules have been theoretically investigated by using CPHF/6-31G method. The first hyperpolarizabilities (${\beta}$) of p-nitrobenzene derivatives increase with the donor in the order, $NH_2\;<\;NMe_2\;<\;NMePh\;<\;NPh_2$, whereas slightly different order is observed in more conjugated derivatives, i.e., $NH_2\;<\;NPh_2\;<\;NMe_2\;<\;NMePh$. The result has been attributed to the extent of charge transfer and torsion angle. Moreover, the results show that "non-traditional" ${\pi}$-conjugation effect exists in small compounds and decreases as the conjugation length between donor and acceptor increases.

• Bulletin of the Korean Chemical Society
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• v.24 no.8
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• pp.1051-1052
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• 2003

• Bulletin of the Korean Chemical Society
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• v.25 no.9
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• pp.1427-1429
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• 2004

• Proceedings of the Optical Society of Korea Conference
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• 2002.11a
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• pp.274-275
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• 2002

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.5 no.3
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• pp.240-249
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• 1995

Rutile type of $TiO_{2}$ single crystal was grown by floating zone method in order to obtain the highly transparent and contamination-free single crystal. The linear refractive index of perpendicular and parallel to c-axis was measured as a function o f wavelength from 500 to 1000nm. The optical energy band gap was estimated as 2.99 eV from the absorption spectrum. The theoretical $\chi^{(3)}$} value of $TiO_{2}$ was discussed in comparison with that of $SiO_{2}$ quartz single crystal on the basis of semiempirical model. On the other hand, the second-hyperpolarizability, ${\gamma}({Ti}^{4+})$ was calculated in order to describe the effect of $Ti_{4}$ ion on the third order nonlinear optical properties.

• Proceedings of the Optical Society of Korea Conference
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• 2003.02a
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• pp.24-25
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• 2003

새로이 합성된 비선형 광학 물질인 옥타폴 분자들의 1차 초분극율ß을 Hyper-Rayleigh scattering(HRS) 방법을 이용하여 측정하였다. 시료의 흡수와 형광효과를 피하기 위해, 광원으로 1560nm를 사용하였다. YAG(1064nm) 레이저로 펌핑한 Raman-Cell(D$_2$ gas) 장치를 제작하여, 높고 안정한 파워의 1560nm를 발생하여 실험에 사용하였다. 또한 1064nm를 이용하여 측정한 결과와 비교하였다. (중략)

• Korean Journal of Optics and Photonics
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• v.11 no.1
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• pp.25-32
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• 2000

Comparisons are made between the first hyperpolarizability $\beta$ of pure N-(4-nitrophenyl)-(L)-prolinol (NPP) and poly (methyl metacrylate) (PMMA) or poly-p-(phenylene terephthalates) (PPT) with NPP side group determined with two different methods, electric-field-induced second-harmonic generation (EFISHG) and hyper-Rayleigh scattering (HRS) methods. Both techniques yield the same values within the experimental errors for pure NPP and NPP-PMMA in 1,1,2,2-tetrachloroethane solution. But the measured results of NPP-PPT polymer in 1,1,2,2-tetrachloroethane solution are showing that the first hyperpolarizability was enhanced with an enhencement of a factor 9.7 in EFISHG and a factor 2.4 in HRS relative to pure NPP. These results indicate that nonlinear optical chromophores organized as side groups of polymers with a rigid backbone contribute coherently to the secondorder nonlinear response of the polymer in the dc electric field as polar polymer chains. hains.

• Bulletin of the Korean Chemical Society
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• v.35 no.5
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• pp.1391-1396
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• 2014

In the present study, ten metal free non-linear optical (NLO) compounds have been designed. These compounds have designed by structural modification of (2-cyano-5-(4-(phenyl(4-vinylphenyl)amino)phenyl) penta-2,4-dienoic acid (TC4). Density functional theory was used for structure optimization and determination of photo-physical properties. These compounds contain triphenylamine as electron-donor and cyanoacrylic acid as acceptor. Five ${\pi}$-spacers are used to connect the donor and acceptor. Two auxiliary donors are also used to assist the donor. Results of this study indicate that stronger electron-donating auxiliary groups and longer ${\pi}$-conjugation enhance NLO response. Major absorption peaks of all systems were in the visible region. These absorption peaks are associated with the ${\pi}-{\pi}^*$ transitions of the entire molecule. From calculations it is clear that all system will be good NLO material. The present calculations will provide new ways for experimentalists to synthesize high-performance NLO material.

• Proceedings of the Optical Society of Korea Conference
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• 2002.07a
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• pp.104-105
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• 2002

Hyper-Rayleigh scattering(HRS)방법을 이용하여 쌍극자와 새로이 합성된 팔중극자들의 1차 초분극율 $\beta$를 측정하였다. External reference 법을 이용하였고, reference 물질로는 잘 알려져 있는 쌍극자인 PNA를 이용하여 Disperse Red 1과 팔중극자들의 1차 초분극율 $\beta$의 값을 구하였다. 또한 HRS 의 세기뿐만 아니라 이들 물질의 two-photon induced fluorescence 스펙트럼을 측정하였다. 1차 초분극율 $\beta$값은, 먼저 시료로부터 scattering 된 신호를 파장변화에 따른 스펙트럼으로 측정하여 two-photon induced fluorescence를 뺀 순수한 HRS 신호만을 이용하고, 실험에 사용된 물질들은 532nm에서 흡수가 있어 second harmonic generation 신호가 시료에 의해 흡수가 되므로 흡수효과를 식 $I_{2{\omega}}$(obs)= $I_{2{\omega}}$(true) $e^{-{\sigma}lN}$ ---(1)를 이용하여 흡수에 의한 신호의 감소 효과를 보정하여 값을 구했다. (중략)

• Journal of the Korean Chemical Society
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• v.57 no.4
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• pp.461-471
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• 2013

Optimized geometrical structure, atomic charges, molecular electrostatic potential, nonlinear optical (NLO) effects and thermodynamic properties of the title compound N-(2,5-methylphenyl)salicylaldimine (I) have been investigated by using ab initio quantum chemical computational studies. Calculated results showed that the enol form of (I) is more stable than keto form. The solvent effect was investigated for obtained molecular energies, hardneses and the atomic charge distributions of (I). Natural bond orbital and frontier molecular orbital analysis of the title compound were also performed. The total molecular dipole moment (${\mu}$), linear polarizability (${\alpha}$), and first-order hyperpolarizability (${\beta}$) were calculated by B3LYP method with 6-31G(d), 6-31+G(d,p), 6-31++G(d,p), 6-311+G(d) and 6-311++G(d,p) basis sets to investigate the NLO properties of the compound (I). The standard thermodynamic functions were obtained for the title compound with the temperature ranging from 200 to 450 K.