Biomedical subjects

Candace C Joyner

Publications and source records attributed to Candace C Joyner.

5 recordsLinked to original sources

PubMed2006

Vibrational and vibronic processes in coherent 2D resonance Raman spectroscopy.

Coherent 2D resonance Raman spectroscopy is a multidimensional technique that is capable of separating and sorting peaks that appear heavily congested and disordered in conventional 1D spectra. It can sort rovibrational peaks according to rotational and vibrational quantum number, vibrational sequence, and rotational selection rule. New results suggest that pattern recognition methods can also be used to determine whether the highly detailed rovibrational information is coming from the ground electronic state or the excited electronic state. This capability is demonstrated using experimental results from I(2) and C(2).

Carbon↗

PubMed2005

Peak separation and sorting by coherent 2D resonance Raman spectroscopy.

The ability to separate and sort peaks is explored using a new coherent two-dimensional form of resonance Raman spectroscopy. This experimental technique distributes normally congested rotational-vibrational peaks along a series of curved lines according to vibrational sequence, rotational quantum number, and selection rule. Each line consists of rotational-vibrational peaks that have the same vibrational sequence and the same value for DeltaJ, distributed in order by rotational quantum number. For diatomic molecules, these lines originate from points where they initially travel in opposite or orthogonal directions in two-dimensional space, which helps facilitate the separation between lines. Simulations and experimental results on C2 in a flame confirm the ability to separate and sort these normally congested rotational-vibrational peaks. This method appears to provide a solution to the long-standing problems of spectral congestion and disorder in gas-phase electronic spectra.

Computer Simulation↗

PubMed2005

High-speed gas chromatography-multiplex coherent Raman analysis of BTEX.

Gas chromatography-multiplex coherent Raman (GC-MCR) is a new tandem technique that can be used for the high-speed analysis of volatile mixtures. BTEX serves as a useful and challenging test sample because of the similarity in boiling point and spectroscopic properties of its constituents. The ability to spectroscopically resolve isomers (e.g., m-xylene and p-xylene) allows GC-MCR to sacrifice chromatographic resolution for speed. The result is the analysis of BTEX in less than 5 min, which is relatively fast compared with other tandem GC techniques.

Chromatography, Gas↗

PubMed2003

Gas chromatography-multiplex coherent Raman spectroscopy.

A new detector for gas chromatography has been developed that is based upon nonlinear Raman spectroscopy. The resulting hyphenated instrument uses a simple windowless cell as the interface between the chromatograph and the spectroscopic detector. The eluents are detected using a unique spectrometer equipped with a broadband OPO. This spectrometer is capable of generating high-resolution coherent Raman signals that are suitable for rapid multichannel detection.

Chromatography, Gas↗

PubMed2002

High-speed high-resolution gas-phase Raman spectroscopy.

A new Raman spectrometer has been developed that can produce a complete high-resolution gas-phase vibrational spectrum during the time period of a single laser pulse. Conventional gas-phase Raman spectroscopy uses a single narrow-band laser to produce signals that are weak, requiring relatively long collection times. This spectrometer uses a degenerate OPO as a broad-band source that covers a continuous range of >3000 cm(-1). When a beam from this broad-band source is added to a narrow-band laser beam, the intensity of the Raman signal is amplified by the nonlinear optical effect. The resulting instrument can generate spectra with high-spectral (<1 cm(-1)), spatial (<0.05 mm2), and temporal resolution (<1 s).

Fourier Analysis↗