scholarly journals Application of Infrared Multiple Photon Dissociation (IRMPD) Spectroscopy in Chiral Analysis

Molecules ◽  
2020 ◽  
Vol 25 (21) ◽  
pp. 5152
Author(s):  
Yingying Shi ◽  
Mengying Du ◽  
Juan Ren ◽  
Kailing Zhang ◽  
Yicheng Xu ◽  
...  
Keyword(s):  
Ion Trap ◽  
Structural Information ◽  
Theoretical Calculations ◽  
Chiral Discrimination ◽  
Chiral Analysis ◽  
Chiral Molecules ◽  
Chiral Complexes ◽  
Irmpd Spectroscopy ◽  
Infrared Multiple Photon Dissociation ◽  
The Difference

In recent years, methods based on photodissociation in the gas phase have become powerful means in the field of chiral analysis. Among them, infrared multiple photon dissociation (IRMPD) spectroscopy is a very attractive one, since it can provide valuable spectral and structural information of chiral complexes in addition to chiral discrimination. Experimentally, the method can be fulfilled by the isolation of target diastereomeric ions in an ion trap followed by the irradiation of a tunable IR laser. Chiral analysis is performed by comparing the difference existing in the spectra of enantiomers. Combined with theoretical calculations, their structures can be further understood on the molecular scale. By now, lots of chiral molecules, including amino acids and peptides, have been studied with the method combined with theoretical calculations. This review summarizes the relative experimental results obtained, and discusses the limitation and prospects of the method.

scholarly journals On the Proton-Bound Noble Gas Dimers (Ng-H-Ng)+ and (Ng-H-Ng')+ (Ng, Ng'= He-Xe): Relationships betweenStructure, Stability, and Bonding Character

Molecules ◽  
2021 ◽  
Vol 26 (5) ◽  
pp. 1305
Author(s):  
Stefano Borocci ◽  
Felice Grandinetti ◽  
Nico Sanna
Keyword(s):  
Theoretical Calculations ◽  
Noble Gas ◽  
Structure Stability ◽  
Covalent Bonds ◽  
Dissociation Energies ◽  
Non Covalent Interactions ◽  
The Difference ◽  
Noble Gas Dimers ◽  
Covalent Interactions ◽  
Cluster Level

The structure, stability, and bonding character of fifteen (Ng-H-Ng)+ and (Ng-H-Ng')+ (Ng, Ng' = He-Xe) compounds were explored by theoretical calculations performed at the coupled cluster level of theory. The nature of the stabilizing interactions was, in particular, assayed using a method recently proposed by the authors to classify the chemical bonds involving the noble-gas atoms. The bond distances and dissociation energies of the investigated ions fall in rather large intervals, and follow regular periodic trends, clearly referable to the difference between the proton affinity (PA) of the various Ng and Ng'. These variations are nicely correlated with the bonding situation of the (Ng-H-Ng)+ and (Ng-H-Ng')+. The Ng-H and Ng'-H contacts range, in fact, between strong covalent bonds to weak, non-covalent interactions, and their regular variability clearly illustrates the peculiar capability of the noble gases to undergo interactions covering the entire spectrum of the chemical bond.

scholarly journals Microsolvation of Zn cations: infrared multiple photon dissociation spectroscopy of Zn+(H2O)n (n = 2–35)

2021 ◽  
Vol 23 (5) ◽  
pp. 3627-3636
Author(s):  
Ethan M. Cunningham ◽  
Thomas Taxer ◽  
Jakob Heller ◽  
Milan Ončák ◽  
Christian van der Linde ◽  
...  
Keyword(s):  
Density Functional Theory ◽  
Density Functional ◽  
Functional Theory ◽  
Irmpd Spectroscopy ◽  
Infrared Multiple Photon Dissociation

The structures, along with solvation evolution, of size-selected Zn+(H2O)n (n = 2–35) complexes have been determined by combining infrared multiple photon photodissociation (IRMPD) spectroscopy and density functional theory.

Periodically poled KTA crystal investigated using coherent X-ray beams

2000 ◽  
Vol 33 (4) ◽  
pp. 1149-1153 ◽  
Author(s):  
P. Pernot-Rejmánková ◽  
P. A. Thomas ◽  
P. Cloetens ◽  
F. Lorut ◽  
J. Baruchel ◽  
...  
Keyword(s):  
Phase Difference ◽  
Domain Walls ◽  
Structural Information ◽  
Periodically Poled ◽  
Synchrotron Source ◽  
X Ray ◽  
Diffracted Waves ◽  
Coherent Beams ◽  
Diffraction Imaging ◽  
The Difference

The distribution of inverted ferroelectric domains on the surface and within the bulk of a periodically poled KTA (KTiOAsO4) single crystal has been observed using a simple X-ray diffraction imaging setup which takes advantage of the highly coherent beams available at a third-generation synchrotron source, such as the ESRF. This technique allows one to reveal the phase difference between the waves that are Bragg diffracted from adjacent domainsviafree-space propagation (Fresnel diffraction). The phase difference of the diffracted waves is mainly produced by the difference in phases of the structure factors involved, and contains precise structural information about the nature of the domain walls.

The kinetics of Ge lateral overgrowth on SiO2

MRS Advances ◽  
2015 ◽  
Vol 1 (23) ◽  
pp. 1703-1708 ◽  
Author(s):  
M. Yako ◽  
N. J. Kawai ◽  
Y. Mizuno ◽  
K. Wada
Keyword(s):  
Growth Kinetics ◽  
Growth Rates ◽  
Growth Process ◽  
Theoretical Calculations ◽  
Film Formation ◽  
Lateral Overgrowth ◽  
Flat Film ◽  
The Difference ◽  
Kinetics Of

ABSTRACTThe kinetics of Ge lateral overgrowth on SiO2 with line-shaped Si seeds is examined. The growth process is described by the difference between the growth rates of Ge on (100) planes (GR100) and <311> facets (GR311). The theoretical calculations well reproduce the growth kinetics. It is shown that narrowing the line-seeds helps Ge coalescence and flat film formation.

scholarly journals Anharmonicity and Spectra–Structure Correlations in MIR and NIR Spectra of Crystalline Menadione (Vitamin K3)

Molecules ◽  
2021 ◽  
Vol 26 (22) ◽  
pp. 6779
Author(s):  
Krzysztof B. Beć ◽  
Justyna Grabska ◽  
Christian W. Huck ◽  
Sylwester Mazurek ◽  
Mirosław A. Czarnecki
Keyword(s):  
Single Molecule ◽  
Near Infrared ◽  
Structural Information ◽  
Molecular System ◽  
Theoretical Calculations ◽  
Vitamin K3 ◽  
Structure Correlations ◽  
Mir Spectra ◽  
Combination Bands ◽  
The Relationship

Mid-infrared (MIR) and near-infrared (NIR) spectra of crystalline menadione (vitamin K3) were measured and analyzed with aid of quantum chemical calculations. The calculations were carried out using the harmonic approach for the periodic model of crystal lattice and the anharmonic DVPT2 calculations applied for the single molecule model. The theoretical spectra accurately reconstructed the experimental ones permitting for reliable assignment of the MIR and NIR bands. For the first time, a detailed analysis of the NIR spectrum of a molecular system based on a naphthoquinone moiety was performed to elucidate the relationship between the chemical structure of menadione and the origin of the overtones and combination bands. In addition, the importance of these bands during interpretation of the MIR spectrum was demonstrated. The overtones and combination bands contribute to 46.4% of the total intensity of menadione in the range of 3600–2600 cm−1. Evidently, these bands play a key role in shaping of the C-H stretching region of MIR spectrum. We have shown also that the spectral regions without fundamentals may provide valuable structural information. For example, the theoretical calculations reliably reconstructed numerous overtones and combination bands in the 4000–3600 and 2800–1800 cm−1 ranges. These results, provide a comprehensive origin of the fundamentals, overtones and combination bands in the NIR and MIR spectra of menadione, and the relationship of these spectral features with the molecular structure.

scholarly journals Fuzzy Knowledge Distance with Three-Layer Perspectives in Neighborhood System

2021 ◽  
Vol 2021 ◽  
pp. 1-15
Author(s):  
Jie Yang ◽  
Tian Luo ◽  
Fan Zhao ◽  
Shuai Li ◽  
Wei Zhou
Keyword(s):  
Rough Sets ◽  
Structural Information ◽  
Boundary Region ◽  
Basic Element ◽  
Target Concept ◽  
Information Granule ◽  
Density Peaks ◽  
Neighborhood System ◽  
Neighborhood Rough Sets ◽  
The Difference

Information granule is the basic element in granular computing (GrC), and it can be obtained according to the granulation criterion. In neighborhood rough sets, current uncertainty measures focus on computing the knowledge granulation of single granular space and have two main limitations: (i) neglecting the structural information of boundary regions and (ii) the inability to reflect the difference between neighborhood granular spaces with the same uncertainty for approximating a target concept. Firstly, a fuzziness-based uncertainty measure for neighborhood rough sets is introduced to characterize the structural information of boundary regions. Moreover, from the perspective of distance, based on the idea of density peaks, we present a fuzzy-neighborhood-granule-distance- (FNGD-) based method to discover the relationship between granules in a granular space. Then, to characterize the difference between granular spaces for approximating a target concept, we present the fuzzy neighborhood granular space distance (FNGSD) and fuzzy neighborhood boundary region distance (FNBRD). FNGD, FNGSD, and FNBRD are hierarchically organized from fineness to coarseness according to the semantics of granularity, which provide three-layer perspectives in the neighborhood system.

scholarly journals Oxidation of Sodium Deoxycholate Catalyzed by Gold Nanoparticles and Chiral Recognition Performances of Bile Salt Micelles

Molecules ◽  
2019 ◽  
Vol 24 (24) ◽  
pp. 4508
Author(s):  
Jing Wang ◽  
Xu Xu ◽  
Hao Chen ◽  
Shuai-Shuai Zhang ◽  
Yin-Xian Peng
Keyword(s):  
Oxidation Product ◽  
Mass Spectra ◽  
Uv Light ◽  
Sodium Deoxycholate ◽  
Chiral Discrimination ◽  
Alkaline Condition ◽  
Chiral Model ◽  
Mixed Solution ◽  
Gold Nps ◽  
The Difference

Au nanoparticles (NPs) were prepared by UV light irradiation of a mixed solution of HAuCl4 and sodium deoxycholate (NaDC) under alkaline condition, in which NaDC served as both reducing agent and capping agent. The reaction was monitored by circular dichroism (CD) spectra, and it was found that the formed gold NPs could catalyze the oxidation of NaDC. A CD signal at ~283 nm in the UV region was observed for the oxidation product of NaDC. The intensity of the CD signal of the oxidation product was enhanced gradually with the reaction time. Electrospray ionization (ESI) mass spectra and nuclear magnetic resonance (NMR) spectra were carried out to determine the chemical composition of the oxidation product, revealing that NaDC was selectively oxidized to sodium 3-keto-12-hydroxy-cholanate (3-KHC). The chiral discrimination abilities of the micelles of NaDC and its oxidation product, 3-KHC, were investigated by using chiral model molecules R,S-1,1′-Binaphthyl-2,2′-diyl hydrogenphosphate (R,S-BNDHP). Compared with NaDC, the micelles of 3-KHC displayed higher binding ability to the chiral model molecules. In addition, the difference in binding affinity of 3-KHC micelles towards R,S-isomer was observed, and S-isomer was shown to preferentially bind to the micelles.

NANOMECHANICS OF THE RUBBER–FILLER INTERFACE

2017 ◽  
Vol 90 (2) ◽  
pp. 272-284 ◽  
Author(s):  
Ken Nakajima ◽  
Makiko Ito ◽  
Hung Kim Nguyen ◽  
Xiaobin Liang
Keyword(s):  
Structural Information ◽  
Relaxation Modulus ◽  
Rubber Matrix ◽  
Interfacial Region ◽  
Segmental Dynamics ◽  
Static Modulus ◽  
Atomic Force ◽  
Property Evaluation ◽  
The Difference ◽  
Rubber Filler

ABSTRACT Atomic force microscope (AFM)–based nanomechanics is one of the most promising tools for accessing the rubber–filler interface while providing not only structural information but also mechanical–property evaluation. An AFM-based static modulus map is used to close in on the understanding of the filler reinforcement effect. As an example, a famous Guth–Gold equation is verified by comparing tensile testing and AFM. Two different novel methods are also introduced to visualize viscoelastic quantities such as storage and loss moduli, loss tangent, relaxation modulus, and viscosity. The difference in segmental dynamics between a rubber matrix and an interfacial region will be reviewed.

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