Determination of intervalley scattering time in germanium by subpicosecond time-resolved Raman spectroscopy

1993 ◽  
Vol 71 (12) ◽  
pp. 1935-1938 ◽  
Author(s):  
Koichiro Tanaka ◽  
Hideyuki Ohtake ◽  
Tohru Suemoto
Keyword(s):  
Raman Spectroscopy ◽  
Time Resolved ◽  
Intervalley Scattering ◽  
Scattering Time

scholarly journals Determination of the Lowest Excited State of Metal Complexes of Dipyrido[3, 2-a:2′,3′-c]Phenazine

1999 ◽  
Vol 19 (1-4) ◽  
pp. 287-289
Author(s):  
Mark R. Waterland ◽  
Keith C. Gordon
Keyword(s):  
Raman Spectroscopy ◽  
Excited State ◽  
Metal Complexes ◽  
Excited States ◽  
Copper Complexes ◽  
Resonance Raman Spectroscopy ◽  
Resonance Raman ◽  
Time Resolved ◽  
State Data

The nature of the lowest excited state of rhenium and copper complexes of dipyrido[3,2- a:2′ ,3′-c]phenazine (Dppz) has been determined using Resonance Raman, Time- Resolved Resonance Raman Spectroscopy and Spectroelectrochemistry. Comparison of spectroelectrochemical data and excited state data show that for the complexes studied no reduced ligand bands are observed in the excited state spectra thus the lowest excited states are all Ligand Centred in nature. The use of substituents at the 11 and/or 12 position of the ligand has no effect on the excited state ordering.

scholarly journals Analyzing Raman spectral data without separabiliy assumption

2021 ◽  
Author(s):  
Konstantin Fackeldey ◽  
Jonas Röhm ◽  
Amir Niknejad ◽  
Surahit Chewle ◽  
Marcus Weber
Keyword(s):  
Raman Spectroscopy ◽  
Data Matrix ◽  
Time Interval ◽  
Matrix Product ◽  
Time Resolved ◽  
Vibration Spectra ◽  
Novel Approach ◽  
Raman Spectral Data ◽  
Raman Spectral

AbstractRaman spectroscopy is a well established tool for the analysis of vibration spectra, which then allow for the determination of individual substances in a chemical sample, or for their phase transitions. In the time-resolved-Raman-sprectroscopy the vibration spectra of a chemical sample are recorded sequentially over a time interval, such that conclusions for intermediate products (transients) can be drawn within a chemical process. The observed data-matrix M from a Raman spectroscopy can be regarded as a matrix product of two unknown matrices W and H, where the first is representing the contribution of the spectra and the latter represents the chemical spectra. One approach for obtaining W and H is the non-negative matrix factorization. We propose a novel approach, which does not need the commonly used separability assumption. The performance of this approach is shown on a real world chemical example.

Determination of Human Coronary Artery Composition by Raman Spectroscopy

Circulation ◽  
1997 ◽  
Vol 96 (1) ◽  
pp. 99-105 ◽  
Author(s):  
James F. Brennan ◽  
Tjeerd J. Römer ◽  
Robert S. Lees ◽  
Anna M. Tercyak ◽  
John R. Kramer ◽  
...  
Keyword(s):  
Raman Spectroscopy ◽  
Coronary Artery ◽  
Human Coronary Artery

Multivariate Analysis Aided Surface-Enhanced Raman Spectroscopy (MVA-SERS) Multiplex Quantitative Detection of Trace Fentanyl in Illicit Drug Mixtures Using a Handheld Raman Spectrometer

2021 ◽  
pp. 000370282110329
Author(s):  
Ling Wang ◽  
Mario O. Vendrell-Dones ◽  
Chiara Deriu ◽  
Sevde Doğruer ◽  
Peter de B. Harrington ◽  
...  
Keyword(s):  
Raman Spectroscopy ◽  
Principal Component ◽  
Surface Enhanced Raman Spectroscopy ◽  
Quantitative Detection ◽  
Least Squares Regression ◽  
Surface Enhanced ◽  
Surface Enhanced Raman ◽  
Sers Detection ◽  
Current Screening

Recently there has been upsurge in reports that illicit seizures of cocaine and heroin have been adulterated with fentanyl. Surface-enhanced Raman spectroscopy (SERS) provides a useful alternative to current screening procedures that permits detection of trace levels of fentanyl in mixtures. Samples are solubilized and allowed to interact with aggregated colloidal nanostars to produce a rapid and sensitive assay. In this study, we present the quantitative determination of fentanyl in heroin and cocaine using SERS, using a point-and-shoot handheld Raman system. Our protocol is optimized to detect pure fentanyl down to 0.20 ± 0.06 ng/mL and can also distinguish pure cocaine and heroin at ng/mL levels. Multiplex analysis of mixtures is enabled by combining SERS detection with principal component analysis and super partial least squares regression discriminate analysis (SPLS-DA), which allow for the determination of fentanyl as low as 0.05% in simulated seized heroin and 0.10% in simulated seized cocaine samples.

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