• Proceedings of the Korean Vacuum Society Conference
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• 2010.08a
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• pp.64-64
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• 2010

Ice film surfaces were examined by using the reactive ion scattering (RIS) of low energy (<35 eV) cesium ion beams. Neutral molecules (X) on the surface were detected in the form of cesium-molecule ion clusters (CsX+). Ionic species on the surface were desorbed from the surface via a low energy sputtering (LES) process below the threshold energy of secondary ion emission. The RIS and LES methods allowed us to study the H/D exchange reactions between H2O and D2O molecules on the surface and the associated proton transfer mechanisms. Specifically, H/D exchange kinetics was examined for D2O ice films (~10 BL) covered with a small amount of H2O (<0.5 BL), in the presence or absence of HCl adsorbates which provided excess protons on the surface.

• Bulletin of the Korean Chemical Society
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• v.31 no.2
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• pp.271-272
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• 2010

• Bulletin of the Korean Chemical Society
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• v.29 no.11
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• pp.2183-2188
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• 2008

• Bulletin of the Korean Chemical Society
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• v.29 no.4
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• pp.725-726
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• 2008

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.15 no.6
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• pp.471-478
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• 2002

Vacuum evaporated cadmium sulphide (CdS) thin films were implanted with $Ar^+$ and $N^+$ for different doses. The properties of the ion implanted CdS thin films have been analysed using XRD, optical transmittance spectra, and Raman scattering studies. Formation of Cd metallic clusters were observed in ion implanted films. The band gap of $Ar^+$ doped films decreased from 2.385 eV of the undoped film to 2.28 eV for the maximum doping. In the case of $N^+$ doped film the band gap decreased from 2.385 to 2.301 eV, whereas the absorption coefficient values increased with the increase of implantation dose. On implantation of both types of ions, the Raman peak position appeared at $299\textrm{cm}^{-1}$ and the FWHM changed with the ion dose.

• Bulletin of the Korean Chemical Society
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• v.30 no.11
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• pp.2661-2664
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• 2009

Photodissociation of nitrous oxide near 203 nm has been studied by a combination of high resolution slice ion imaging technique and (2+1) resonance-enhanced multiphoton ionization (REMPI) spectroscopy of $N_2(X^1{{\Sigma}_g}^+)$ via the (a″$^1{{\Sigma}_g}^+$) state. We have measured the recoil velocity and angular distributions of $N_2$ fragments by ion images of the state-resolved photofragments. The $N_2$ fragments were highly rotationally excited and the NN-O bond dissociation energy was determined to be 3.635 eV. Also, we investigated the photofragment images from the photodissociation of $N_2O$ clusters with various stagnation pressures.

• Bulletin of the Korean Chemical Society
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• v.18 no.3
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• pp.296-300
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• 1997

The intracluster ion/molecule reactions within 1,1-difluoroethene homocluster have been studied by electron-impact quadrupole mass spectrometry. When CH2CF2 seeded in helium is expanded and ionized by electron impact, two different types of ion/molecule association (polymerization) reaction products, i.e., (CH2CF2)n+ (n≥l) and (CF2CH2)qX+ (X=fragment species, q≤n), are formed. The higher association products, (CH2CF2)n+ (n=3, 4), have shown stronger intensities over the lower association product, (CH2CF2)2+, in the low electron impact energy region ( < 39 eV). These stronger intensities are interpreted in terms of the stabilization of these ions due to the ring formations over the dimer ion in this energy region. The evidence of ring formation mechanism is on the basis of the intensity distribution of fragments at various electron impact energy. In another typical branched-chain growth reaction of these compounds, the F-shift reaction path is found to be more favorable energetically than the H-shift via the fragment patterns of clusters and semi-empirical calculation.

• Proceedings of the Korea Association of Crystal Growth Conference
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• 1999.06a
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• pp.115-127
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• 1999

The charged clusters or particles, which contain hundreds to thousands of atoms or even more, are suggested to form in the gas phase in the thin film processes such as CVD, thermal evaporation, laser ablation, and flame deposition. All of these processes are also used in the gas phase synthesis of the nanoparticles. Ion-induced or photo-induced nucleation is the main mechanism for the formation of these nanoclusters or nanoparticles inthe gas phase. Charged clusters can make a dense film because of its self-organizing characteristics while neutral ones make a porous skeletal structure because of its Brownian coagulation. The charged cluster model can successfully explain the unusual phenomenon of simultaneous deposition and etching taking place in diamond and silicon CVD processes. It also provides a new interpretation on the selective deposition on a conducting material in the CVDd process. The epitaxial sticking of the charged clusters on the growing surface is gettign difficult as the cluster size increases, resulting in the nanostructure such as cauliflowr or granular structures.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.9 no.3
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• pp.289-294
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• 1999

The charged clusters or particles, which contain hundreds to thousands of atoms or even more, are suggested to from in the gas phase in the thin film processes such as CVD, thermal evaporation, laser ablation, and flame deposition. All of these processes are also phase synthesis of the nanoparticels. Ion-induced or photo-induced nucleation is the main mechanism for the formation of these nanoclusters or nanoparticles in the gas phase. Charge clusters can make a dense film because of its self-organizing characteristics while neutral ones make a porous skeletal structure because of its Brownian coagulation. The charged cluster model can successfully explain the unusual phenomenon of simultaneous deposition and etching taking place in diamond and silicon CVD processes. It also provides a new interpretation on the selective deposition on a conducting material in the CVD process. The epitaxial sticking of the charged clusters on the growing surface is getting difficult as the cluster size increases, resulting in the nanostructure such as cauliflower or granular structures.

• Journal of Magnetics
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• v.17 no.4
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• pp.251-254
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• 2012

The electron paramagnetic resonance (EPR) of the $Eu^{2+}$ ion in $SrCl_2$:Eu single crystal has been investigated using an X-band spectrometer. The angular dependence of magnetic resonance positions for the $Eu^{2+}$ impurity ion in the crystallographic aa-plane is analyzed with effective spin-Hamiltonian. The EPR spectra of the isolated $Eu^{2+}$ center merged to each other. The hyperfine splitting of the isolated $Eu^{2+}$ center due to the $^{151}Eu$ nucleus is approximately 35 G. Three kinds of $Eu^{2+}$ centers except the isolated $Eu^{2+}$ center, $Eu^{2+}$ pairs, $Eu^{2+}$ triples, and other $Eu^{2+}$ clusters, are split from the fitting of the integrated experimental spectrum with the Gaussian curve. The calculated spectroscopic splitting parameters of the $Eu^{2+}$ pairs, $Eu^{2+}$ triples, and other $Eu^{2+}$ clusters in $SrCl_2$:Eu crystal are $g_1$ = 2.06, $g_2$ = 1.94, and $g_3$ = 1.93, respectively.