Spectral signatures of semiconductor clusters: (CdSe)16 isomers

Gutsev, Lavrenty G.; Dalal, Naresh S.; Ramachandran, B.; Weatherford, Charles A.; Gutsev, G. L.

doi:10.1016/j.cplett.2015.07.024

Cited by 9 publications

(9 citation statements)

References 49 publications

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“…While these structures are similar, they have different point groups ( D 2 for (CdSe) 16 , T h for (CdS) 16 ). These structures are also similar to the structure used in the spectra calculation reported by Gutsev et al, although the point group is different. (CdS) 15 and (CdS) 18 are both tubelike, with the former being shorter.…”

Section: Minimum-energy Structures Of (Cdx) N Nanoclusterssupporting

confidence: 81%

Structures of CdSe and CdS Nanoclusters from Ab Initio Random Structure Searching

Tan

Pickard

et al. 2019

J. Phys. Chem. C

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The possible structures of (CdSe) n and (CdS) n (n up to 34) nanoclusters were systematically studied using the ab initio random structure searching (AIRSS) method. We have been able to find stable, symmetric nanoclusters not previously discovered; using the computed pair distribution functions, we have put forward a hypothesis for the increased stability of these clusters. We have also been able to investigate structural features of the transformation to the bulk: for (CdS) n with n < 16 and (CdSe) n with n < 21, structures based on rings and cages with coordination number up to 3 are favored, while for larger n, the minimum-energy structures are more bulklike with an average coordination number larger than 3. This indicates a gradual transformation from a cagelike structure to a bulklike structure as the number of atoms increases. One striking finding was that for any value of n, the range of structures formed a continuous distribution of cluster energies rather than there being significant energy differences between them. This work created an extensive database of benchmarks and candidate structures for these systems.

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Section: Minimum-energy Structures Of (Cdx) N Nanoclusterssupporting

confidence: 81%

Structures of CdSe and CdS Nanoclusters from Ab Initio Random Structure Searching

Tan

Pickard

et al. 2019

J. Phys. Chem. C

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“…In most cases, where the experimental geometrical structure is unavailable, the results of measurements by several methods are required for unambiguous identification of isomers. 74 4.2. Interconversion of Isomers.…”

Section: Results Of Computationsmentioning

confidence: 99%

A Theoretical and Mass Spectrometry Study of Dimethyl Methylphosphonate: New Isomers and Cation Decay Channels in an Intense Femtosecond Laser Field

Gutsev

Boateng²,

Jena³

et al. 2017

J. Phys. Chem. A

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Using both mass spectrometry with intense femtosecond laser ionization and high-level computational methods, we have explored the structure and fragmentation patterns of dimethyl methylphosphonate (DMMP) cation. Extensive search of the geometries of both neutral and positively charged DMMP yields new isomers that are appreciably lower in total energy than those commonly synthesized using the Michaelis-Arbuzov reaction. The stability of the standard isomer with CHPO(OCH) topology is found to be due to the presence of high barriers to isomer interconversion that involves several transition states. Our femtosecond laser ionization experiments show that the relative yields of the major dissociation products as a function of peak laser intensity correlate well with the theoretical estimates for the energies of the DMMP decay via various channels. In contrast, the peak laser intensities required for observation of minor dissociation products exhibit no correlation with the computed decay energies, which suggests that barrier heights and/or excited electronic states of DMMP determine its preferred fragmentation pathways in an intense femtosecond laser field.

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“…Our previous study 40 of this dimer has showed that the BPW91/6‐311 + G* approach provides results comparable in accuracy to those obtained by the CCSD(T) method 41 whose results compare well to the experimental data. This functional has shown good performance for related chalcogenide II‐VI semiconductor clusters (CdS) n 42 and (CdSe) n , 43 and the experimental magnetic properties for ZnSe quantum dots doped 5 with Fe have been accurately predicted using this functional. The BPW91 method has been shown to perform quite well in predicting bond energies of a diverse variety of systems when tested against other functionals 44 .…”

Section: Details Of Computationsmentioning

confidence: 92%

Influence of back donation effects on the structure of ZnO nanoclusters

2020

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The structure and properties of ZnO quantum dots is a very popular and rapidly growing field of research for which accurate quantum calculations are challenging to perform. Since the dependence between system size and wall time scales nonlinearly, certain compromises have to be made. A particularly important limiting factor is the size of the basis used, this is especially the case if accurate large calculations are to be carried out. In our work, we discovered that an important O(2p)->Zn(4p) back donation, which greatly influences the strength of the Zn O bond, can be reproduced only if diffuse functions are added to the basis set. We further tested the basis dependence for the magic-sized wurtzite nanophase ZnO clusters which were previously shown to be able to accurately reproduce the magnetically doped II-IV Qdots. In this work, we outline the minimal basis sets required to properly describe Zn O bonds in a nanocluster. It was demonstrated that the rock salt nanophase is incorrectly stabilized if a basis set does not contain sufficiently diffuse functions while the correct wurtzite phase is stabilized when diffuse functions are added. This tendency, similar to that in the ZnO dimer case, was shown to stem from the incorrect lack of Zn(4p) electron density in calculations when using the diffuse-free basis set.

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Spectral signatures of semiconductor clusters: (CdSe)16 isomers

Cited by 9 publications

References 49 publications

Structures of CdSe and CdS Nanoclusters from Ab Initio Random Structure Searching

Structures of CdSe and CdS Nanoclusters from Ab Initio Random Structure Searching

A Theoretical and Mass Spectrometry Study of Dimethyl Methylphosphonate: New Isomers and Cation Decay Channels in an Intense Femtosecond Laser Field

Influence of back donation effects on the structure of ZnO nanoclusters

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