Theoretical Study of Structural and Vibrational Properties of (AlP)n, (AlAs)n, (GaP)n, (GaAs)n, (InP)n, and (InAs)n Clusters with n = 1, 2, 3

Costales, Aurora; Kandalam, Anil K.; Franco, R.; Pandey, Ravindra

doi:10.1021/jp013906f

Cited by 108 publications

(67 citation statements)

References 26 publications

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“…Our calculated lowest energy geometry for In 3 P 3 is almost identical to the work by Costales et al [30]. The structures for In 4 P 4 , In 6 P 6 , and In 9 P 9 are here described for the first time.…”

Section: Methodssupporting

confidence: 85%

“…This potassium is then added to the iron surface. The amount of potassium added to the surface of the iron was calibrated by looking at the temperature programmed desorption (TPD) of the potassium on the iron crystal [30]. Leaving the three filaments to a current of 21 amperes allowed the deposition of about one-tenth of a monolayer every minute.…”

Section: Ultrahigh Vacuum/high-pressure Systemmentioning

confidence: 99%

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Model Catalysis of Ammonia Synthesis ad Iron-Water Interfaces - ASum Frequency Generation Vibrational Spectroscopic Study of Solid-GasInterfaces and Anion Photoelectron Spectroscopic Study of Selected Anionclusters

Ferguson

2005

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The ammonia synthesis reaction has been studied using single crystal model catalysis combined with sum frequency generation (SFG) vibrational spectroscopy.The adsorption of gases N 2 , H 2 , O 2 and NH 3 that play a role in ammonia synthesis have been studied on the Fe(111) crystal surface by sum frequency generation vibrational spectroscopy using an integrated Ultra-High Vacuum (UHV) / highpressure system. SFG spectra are presented for the dissociation intermediates, NH 2 (~3325 cm -1 ) and NH (~3235 cm -1 ) under high pressure of ammonia or equilibrium concentrations of reactants and products on Fe(111) surfaces.Special attention was paid to understand how potassium promotion of the iron catalyst affects the intermediates of ammonia synthesis. An Fe(111) surface promoted with 0.2 monolayers of potassium red shifts the vibrational frequencies of the reactive surface intermediates, NH and NH 2 , providing evidence for weakened the nitrogenhydrogen bonds relative to clean Fe(111). Spectral features of these surface 2 intermediates persisted to higher temperatures for promoted iron surfaces than for clean Fe(111) surfaces implying that nitrogen-iron bonds are stronger for the promoted surface. The ratio of the NH to NH 2 signal changed for promoted surfaces in the presence of equilibrium concentrations of reactants and products. The order of adding oxygen and potassium to promoted surfaces does not alter the spectra indicating that ammonia induces surface reconstruction of the catalyst to produce the same surface morphology.When oxygen is co-adsorbed with nitrogen, hydrogen, ammonia or potassium on Fe(111), a relative phase shift of the spectra occurs as compared to the presence of adsorbates on clean iron surfaces.Water adsorption on iron was also probed using SFG vibrational spectroscopy. For both H 2 O and D 2 O, the only spectral feature was in the range of the free OH or free OD. From the absence of SFG spectra of ice-like structure we conclude that surface hydroxides are formed and no liquid water is present on the surface.Other than model catalysis, gas phase anion photoelectron spectroscopy of the Cl + H 2 van der Waals well, silicon clusters, germanium clusters, aluminum oxide clusters and indium phosphide clusters were studied. The spectra help to map out the neutral potential energy surfaces of the clusters. For aluminum oxide, the structures of the anions and neutrals were explored and for silicon, germanium and indium phosphide the electronic structure of larger clusters was mapped out.

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Section: Methodssupporting

confidence: 85%

Section: Ultrahigh Vacuum/high-pressure Systemmentioning

confidence: 99%

Model Catalysis of Ammonia Synthesis ad Iron-Water Interfaces - ASum Frequency Generation Vibrational Spectroscopic Study of Solid-GasInterfaces and Anion Photoelectron Spectroscopic Study of Selected Anionclusters

Ferguson

2005

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“…GaN clusters have also been studied by Pandey and coworkers (26)(27)(28) as well as others (29)(30)(31)(32). AlP has also been studied by a number of investigators (33)(34)(35)(36)(37). This listing is not exhaustive, but is just meant to give some sense of the breadth of the existing literature in this field.…”

mentioning

confidence: 99%

Surface bonding effects in compound semiconductor nanoparticles: II

Farrell¹

2008

Journal of Vacuum Science &Amp; Technology B: Microelectronics and Nanometer Structures Processing, Measurement, and Phenomena

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Small nanoparticles have a large proportion of their atoms either at or near the surface, and those in clusters are essentially all on the surface. As a consequence, the details of the surface structure are of paramount importance in governing the overall stability of the particle. Just as with bulk materials, factors that determine this stability include "bulk" structure, surface reconstruction, charge balance and hybridization, ionicity, strain, stoichiometry, and the presence of adsorbates. Needless to say, many of these factors, such as charge balance, hybridization and strain, are interdependent. These factors all contribute to the overall binding energy of clusters and small nanoparticles and play a role in determining the deviations from an inverse size dependence that we have previously reported for compound semiconductor materials. Using first-principles density functional theory calculations, we have explored how these factors influence particle stability under a variety of conditions. 2

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“…An important issue in a bottom-up approach to fabricating nanoclusters for future technological applications is an understanding of the evolution of their response properties with cluster size and shape. Theoretical work on atomic clusters of III-V semiconductors have examined the electronic structure and stability of small clusters using density functional theory [4,5] and their linear and non-linear optical properties using the ab initio time dependent HartreeFock formalism [6,7,8] as well as time-dependent density functional theory [9]. Work by Kandalam et al suggests that as cluster sizes increase a transition from low energy planar to bulk-like 3-D structures occurs in some nitrides [4].…”

Section: Introductionmentioning

confidence: 99%

Size-dependence of the Linear and Nonlinear Optical Properties of GaN Nanoclusters

Pineda

Karna

2004

MRS Proc.

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Public reporting burden for this collection of information is estimated to average 1 hour per response, including the time for reviewing instructions, searching existing data sources, gathering and maintaining the data needed, and completing and reviewing this collection of information. Send comments regarding this burden estimate or any other aspect of this collection of information, including suggestions for reducing this burden to Department of Defense, Washington Headquarters Services, Directorate for Information SPONSOR/MONITOR'S ACRONYM(S)AFRL/VSSE SPONSOR/MONITOR'S REPORT NUMBER(S) DISTRIBUTION / AVAILABILITY STATEMENTApproved for public release; distribution is unlimited. SUPPLEMENTARY NOTESPresented at Mater.Res.Soc.Symp.Proc. Vol 846 Government Purpose Rights ABSTRACTIn this paper, we present the results of our first-principles quantum mechanical studies of the electronic structure, geometry, and linear and nonlinear optical (NLO) properties of tetrahedral Ga m N m (m=1, 4, 7, 17) atomic clusters. Our calculated results suggest that the linear and NLO properties both exhibit a strong dependence upon cluster size and shape (geometry). However, the size-and the geometry-dependences are more pronounced for the NLO properties than for the linear optical properties. For clusters containing equal numbers of Ga and N atoms, an open-structure with no network-forming ring has a much larger second-order NLO coefficient than a cluster with a closed ring structure. SUBJECT TERMS ABSTRACTIn this paper, we present the results of our first-principles quantum mechanical studies of the electronic structure, geometry, and linear and nonlinear optical (NLO) properties of tetrahedral Ga m N m (m=1, 4, 7, 17) atomic clusters. Our calculated results suggest that the linear and NLO properties both exhibit a strong dependence upon cluster size and shape (geometry). However, the size-and the geometry-dependences are more pronounced for the NLO properties than for the linear optical properties. For clusters containing equal numbers of Ga and N atoms, an open-structure with no network-forming ring has a much larger second-order NLO coefficient than a cluster with a closed ring structure.

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Theoretical Study of Structural and Vibrational Properties of (AlP)_n, (AlAs)_n, (GaP)_n, (GaAs)_n, (InP)_n, and (InAs)_n Clusters with n = 1, 2, 3

Cited by 108 publications

References 26 publications

Model Catalysis of Ammonia Synthesis ad Iron-Water Interfaces - ASum Frequency Generation Vibrational Spectroscopic Study of Solid-GasInterfaces and Anion Photoelectron Spectroscopic Study of Selected Anionclusters

Model Catalysis of Ammonia Synthesis ad Iron-Water Interfaces - ASum Frequency Generation Vibrational Spectroscopic Study of Solid-GasInterfaces and Anion Photoelectron Spectroscopic Study of Selected Anionclusters

Surface bonding effects in compound semiconductor nanoparticles: II

Size-dependence of the Linear and Nonlinear Optical Properties of GaN Nanoclusters

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