Two-Dimensional (2D) Correlation Analysis and the Search for Intermediates: A Strictly Mathematical Approach to an Important Mechanistic Question

ACS Catalysis ◽  
2015 ◽  
Vol 5 (6) ◽  
pp. 3588-3599 ◽  
Author(s):  
Qisong Xu ◽  
LiangFeng Guo ◽  
Tung Nguyen Dinh ◽  
Angie Cheong ◽  
Marc Garland
Keyword(s):  
Correlation Analysis ◽  
Mathematical Approach ◽  
Two Dimensional ◽  
2D Correlation Analysis

New understanding on the reaction pathways of the polyacrylonitrile copolymer fiber pre-oxidation: online tracking by two-dimensional correlation FTIR spectroscopy

RSC Advances ◽  
2016 ◽  
Vol 6 (6) ◽  
pp. 4397-4409 ◽  
Author(s):  
Jing Zhao ◽  
Jihai Zhang ◽  
Tao Zhou ◽  
Xifei Liu ◽  
Qiang Yuan ◽  
...  
Keyword(s):  
Correlation Analysis ◽  
Ftir Spectroscopy ◽  
Reaction Pathways ◽  
Two Dimensional ◽  
Online Tracking ◽  
Polyacrylonitrile Copolymer ◽  
2D Correlation Analysis

FTIR spectroscopy in combination with scaling-MW2D and 2D correlation analysis is used to study the reaction pathways of polyacrylonitrile copolymer fibers pre-oxidation.

Multiple-perturbation two-dimensional (2D) correlation analysis for spectroscopic imaging data

2014 ◽  
Vol 1069 ◽  
pp. 176-182 ◽  
Author(s):  
Hideyuki Shinzawa ◽  
Kosuke Hashimoto ◽  
Hidetoshi Sato ◽  
Wataru Kanematsu ◽  
Isao Noda
Keyword(s):  
Correlation Analysis ◽  
Spectroscopic Imaging ◽  
Two Dimensional ◽  
Imaging Data ◽  
2D Correlation Analysis

scholarly journals New Approach to Generalized Two-Dimensional Correlation Spectroscopy. 1: Combination of Principal Component Analysis and Two-Dimensional Correlation Spectroscopy

2002 ◽  
Vol 56 (12) ◽  
pp. 1562-1567 ◽  
Author(s):  
Young Mee Jung ◽  
Hyeon Suk Shin ◽  
Seung Bin Kim ◽  
Isao Noda
Keyword(s):  
Principal Component Analysis ◽  
Correlation Analysis ◽  
Principal Component ◽  
Component Analysis ◽  
Correlation Spectroscopy ◽  
Data Matrix ◽  
Two Dimensional ◽  
Noise Component ◽  
Reconstructed Data ◽  
2D Correlation Analysis

The direct combination of chemometrics and two-dimensional (2D) correlation spectroscopy is considered. The use of a reconstructed data matrix based on the significant scores and loading vectors obtained from the principal component analysis (PCA) of raw spectral data is proposed as a method to improve the data quality for 2D correlation analysis. The synthetic noisy spectra were analyzed to explore the novel possibility of the use of PCA-reconstructed spectra, which are highly noise suppressed. 2D correlation analysis of this reconstructed data matrix, instead of the raw data matrix, can significantly reduce the contribution of the noise component to the resulting 2D correlation spectra.

Molecular self-healing mechanisms between C60-fullerene and anthracene unveiled by Raman and two-dimensional correlation spectroscopy

2016 ◽  
Vol 18 (27) ◽  
pp. 17973-17982 ◽  
Author(s):  
R. Geitner ◽  
J. Kötteritzsch ◽  
M. Siegmann ◽  
R. Fritzsch ◽  
T. W. Bocklitz ◽  
...  
Keyword(s):  
Raman Spectroscopy ◽  
Correlation Analysis ◽  
Correlation Spectroscopy ◽  
C60 Fullerene ◽  
Self Healing ◽  
Two Dimensional ◽  
Ft Raman Spectroscopy ◽  
2D Correlation Analysis ◽  
Ft Raman

C60-fullerene–anthracene self-healing copolymers were studied by time-, temperature- and concentration-dependent FT-Raman spectroscopy and advanced 2D correlation analysis.

New Approach to Avoid Erroneous Interpretation of Results Derived from Generalized Two-Dimensional Correlation Analysis for Applications in Catalysis

2005 ◽  
Vol 59 (8) ◽  
pp. 1060-1067 ◽  
Author(s):  
Peter Haider ◽  
Gary L. Haller ◽  
Lisa Pfefferle ◽  
Dragos Ciuparu
Keyword(s):  
Correlation Analysis ◽  
Surface Characterization ◽  
Oscillatory Behavior ◽  
Data Matrix ◽  
Spectral Features ◽  
Two Dimensional ◽  
New Approach ◽  
Set Up ◽  
Time Sequences ◽  
2D Correlation Analysis

Surface characterization and catalysis can significantly benefit from the application of generalized two-dimensional (2D) correlation analysis. This two-dimensional approach allows a better resolution of overlapping peaks, can reveal new features not readily observable in the raw spectra, gives clear evidence for spectral intensities that change as an effect of a perturbation applied to the system, and allows the establishment of time sequences for the changes occurring in different spectral features of interest for determining reaction intermediates and/or mechanisms. The interpretation of the synchronous and asynchronous plots was observed to lead to erroneous time sequences when spectral features change in a nonmonotonic way, such as a biphasic or oscillatory behavior, under the influence of a perturbation. We propose a new approach to the 2D correlation analysis to avoid misinterpretation of the results calculated in the asynchronous plot. Progressive correlation analysis (ProCorA) calculates the synchronous plot from the first two spectra of the data matrix and one spectrum is added at every step of the analysis. The sequence of changes can be set up from the progressive evolution of peaks in both the synchronous and asynchronous plots.

TWO-DIMENSIONAL CORRELATION ANALYSIS OF SUPERCONDUCTING YNi2B2C RAMAN SPECTRA

2005 ◽  
Vol 19 (01n03) ◽  
pp. 281-284 ◽  
Author(s):  
IN-SANG YANG ◽  
YOUNG MEE JUNG ◽  
SEUNG BIN KIM ◽  
M. V. KLEIN
Keyword(s):  
Correlation Analysis ◽  
Temperature Dependence ◽  
Raman Spectra ◽  
Superconducting State ◽  
Superconducting Gap ◽  
Two Dimensional ◽  
Temperature Changes ◽  
Phonon Peak ◽  
Two Peaks ◽  
2D Correlation Analysis

Two-dimensional (2D) correlation analysis is applied to the temperature dependence on the Raman spectra of superconducting YNi 2 B 2 C single crystal. 2D correlation analysis on the temperature dependence of the B 1g superconducting gap peak shows strong correlation with the Ni B 1g phonon peak near 200 cm -1. The analysis on the B 1g phonon peak itself shows that the peak is composed of essentially two peaks at 197 and 203 cm -1, and only the weight of the two peaks changes as the temperature changes. The result suggests that there are two distinctive environments of the Ni - B bonds in YNi 2 B 2 C system at the superconducting state.

On the Normalization Method in Two-Dimensional Correlation Spectra When Concentration is Used as a Perturbation Parameter

2003 ◽  
Vol 57 (2) ◽  
pp. 164-167 ◽  
Author(s):  
Z. W. Yu ◽  
I. Noda
Keyword(s):  
Correlation Analysis ◽  
Intensity Variation ◽  
Perturbation Parameter ◽  
Quantitative Information ◽  
Transformation Process ◽  
Normalization Method ◽  
Two Dimensional ◽  
Absorption Bands ◽  
Data Pretreatment ◽  
2D Correlation Analysis

Data pretreatment is of importance in two-dimensional (2D) correlation analysis when composition is used as a perturbation parameter. For composition-oriented studies, different normalization methods based on both external parameters (i.e., concentration) and internal parameters (i.e., absorbance from individual components) have been compared. It was found that when there is no overlapping between absorption bands of interest, no normalization is needed for data pretreatment. When overlapped bands must be used for 2D correlation analysis, the mean-centered normalization method could be used to obtain correct signs in synchronous spectra for a transformation process in the specific form of A → kC. The intensity of the 2D spectrum, however, may not accurately reflect quantitative information of the overall extent of spectral intensity variation observed during experiments.

scholarly journals Characterization of the Electrochemical Reactions in the Li1+xV3O8/Li Cell by Soft X-ray Absorption Spectroscopy and Two-Dimensional Correlation Analysis

2003 ◽  
Vol 57 (8) ◽  
pp. 984-990 ◽  
Author(s):  
Hyun Chul Choi ◽  
Young Mee Jung ◽  
Seung Bin Kim
Keyword(s):  
Correlation Analysis ◽  
Absorption Spectroscopy ◽  
Extraction Process ◽  
Electrochemical Reactions ◽  
Lithium Content ◽  
Spectral Features ◽  
Two Dimensional ◽  
X Ray ◽  
X Ray Absorption ◽  
2D Correlation Analysis

We applied soft X-ray absorption spectroscopy (XAS) and two-dimensional (2D) correlation analysis to the first lithium insertion–extraction cycle in a Li1+xV3O8/Li cell in order to investigate the electrochemical reactions of lithium with the Li1+xV3O8 electrode. The V LII,III-edge and O K-edge spectra of the Li1+xV3O8 electrode were obtained for varying electrode lithium content. The insertion of lithium leads to the reduction of the V5+ species present in the pristine Li1+xV3O8 electrode, and to the red shift and the broadening of the spectral features of the V LII,III edge compared to those of the pristine electrode. In the extraction process, the main spectral features at the highest value of the extraction of lithium show some differences compared to the features of the pristine electrode spectrum due to the residual lithium ions in the Li1+xV3O8 structure. The O K-edge spectra revealed that the insertion of lithium mainly affects the V 4sp–O 2p bonds and consequently induces a change in bonding geometry. The 2D correlation analysis of these spectra clearly shows that V–O bonds are significantly perturbed by the insertion–extraction of lithium into the Li1+xV3O8 electrode.

Generalized Two-Dimensional Fourier Transform Infrared Photoacoustic Spectral Depth-Profiling Analysis

1997 ◽  
Vol 51 (11) ◽  
pp. 1736-1740 ◽  
Author(s):  
Eric Y. Jiang ◽  
William J. McCarthy ◽  
David L. Drapcho ◽  
Richard A. Crocombe
Keyword(s):  
Correlation Analysis ◽  
Depth Profiling ◽  
Correlation Method ◽  
Digital Signal ◽  
Two Dimensional ◽  
Negative Band ◽  
Ft Ir ◽  
Correlated Signals ◽  
Profiling Analysis ◽  
2D Correlation Analysis

This paper reports the first application of a generalized two-dimensional (G2D) correlation method in photoacoustic spectral depth-profiling analysis of laminate/heterogeneous samples. In this method, photoacoustic magnitude spectra at different modulation frequencies are used to generate two-dimensional (2D) correlation spectra. The relative spatial origins of correlated signals are then determined from the signs of the corresponding contours. The unique features and advantages of this technique over previously reported depth-profiling methods are demonstrated and discussed. These include simplification of step-scan photoacoustic phase-modulation experiments as well as 2D correlation-analysis rules, avoidance of phase-related negative-band ambiguities, and enhancement of both spectral and depth resolutions, etc. The recently developed software-based digital signal-processing (DSP) technique for step-scan photoacoustic measurements offers an efficient means (sampling-depth multiplexing advantage) to collect within a single scan all necessary data for this type of 2D correlation analysis. Index Headings: Photoacoustic; PAS; Two-dimensional; Step-scan; FT-IR; Depth profiling; Polymer films; DSP.

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