Author:
Publisher:
ISBN:
Category :
Languages : en
Pages :
Book Description
A theoretical and experimental investigation of OH saturated fluorescence is described. The goal of the research is to develop a saturated fluorescence technique which will yield accurate molecular number densities over a wide range of flame pressure, temperature, and composition. Experimentally, OH is excited by a ten nanosecond pulse from a Nd:YAG-pumped dye laser tuned to an isolated rotational transition in the (0,0) band of the A2.sigma.-X2 pi electronic system. The resulting fluorescence signal is resolved both spectrally and temporally. Total OH number densities are calculated by collecting fluorescence from the directly excited upper rotational level, and using the balanced cross-rate model to analyze the experimental data. Fluorescence measurements of OH number density agree to within a factor of three with the results of independent OH absorption measurements. Significantly, the ratio of the fluorescence signal to the number density measured by absorption is nearly the same in 30, 100 and 250 torr H2/O2/N2 flat flames, demonstrating the insensitivity of the saturated fluorescence signal to the quenching environment of the radical. Collisional transfer in excited OH is studied by recording the time development of OH fluorescence spectrum. The experimental spectra are compared with the results of time-dependent computer modeling. By varying rotational transfer rates until the calculated and experimental spectra agree, rotational transfer cross sections can be calculated. The signal processing system was thoroughly checked by comparing the photomultiplier output to that of a fast photodiode, and by comparing single pulse Rayleigh scattering and fluorescence traces with sampling oscilloscope traces.
Measurement of Radical-species Concentrations and Polycyclic Aromatic Hydrocarbons in Flames by Fluorescence and Absorption Using a Tunable Dye Laser. Progress Report, March 1, 1980-February 28, 1981
Author:
Publisher:
ISBN:
Category :
Languages : en
Pages :
Book Description
A theoretical and experimental investigation of OH saturated fluorescence is described. The goal of the research is to develop a saturated fluorescence technique which will yield accurate molecular number densities over a wide range of flame pressure, temperature, and composition. Experimentally, OH is excited by a ten nanosecond pulse from a Nd:YAG-pumped dye laser tuned to an isolated rotational transition in the (0,0) band of the A2.sigma.-X2 pi electronic system. The resulting fluorescence signal is resolved both spectrally and temporally. Total OH number densities are calculated by collecting fluorescence from the directly excited upper rotational level, and using the balanced cross-rate model to analyze the experimental data. Fluorescence measurements of OH number density agree to within a factor of three with the results of independent OH absorption measurements. Significantly, the ratio of the fluorescence signal to the number density measured by absorption is nearly the same in 30, 100 and 250 torr H2/O2/N2 flat flames, demonstrating the insensitivity of the saturated fluorescence signal to the quenching environment of the radical. Collisional transfer in excited OH is studied by recording the time development of OH fluorescence spectrum. The experimental spectra are compared with the results of time-dependent computer modeling. By varying rotational transfer rates until the calculated and experimental spectra agree, rotational transfer cross sections can be calculated. The signal processing system was thoroughly checked by comparing the photomultiplier output to that of a fast photodiode, and by comparing single pulse Rayleigh scattering and fluorescence traces with sampling oscilloscope traces.
Publisher:
ISBN:
Category :
Languages : en
Pages :
Book Description
A theoretical and experimental investigation of OH saturated fluorescence is described. The goal of the research is to develop a saturated fluorescence technique which will yield accurate molecular number densities over a wide range of flame pressure, temperature, and composition. Experimentally, OH is excited by a ten nanosecond pulse from a Nd:YAG-pumped dye laser tuned to an isolated rotational transition in the (0,0) band of the A2.sigma.-X2 pi electronic system. The resulting fluorescence signal is resolved both spectrally and temporally. Total OH number densities are calculated by collecting fluorescence from the directly excited upper rotational level, and using the balanced cross-rate model to analyze the experimental data. Fluorescence measurements of OH number density agree to within a factor of three with the results of independent OH absorption measurements. Significantly, the ratio of the fluorescence signal to the number density measured by absorption is nearly the same in 30, 100 and 250 torr H2/O2/N2 flat flames, demonstrating the insensitivity of the saturated fluorescence signal to the quenching environment of the radical. Collisional transfer in excited OH is studied by recording the time development of OH fluorescence spectrum. The experimental spectra are compared with the results of time-dependent computer modeling. By varying rotational transfer rates until the calculated and experimental spectra agree, rotational transfer cross sections can be calculated. The signal processing system was thoroughly checked by comparing the photomultiplier output to that of a fast photodiode, and by comparing single pulse Rayleigh scattering and fluorescence traces with sampling oscilloscope traces.
Energy Research Abstracts
Fossil Energy Update
Government Reports Announcements & Index
Government Reports Annual Index
Author:
Publisher:
ISBN:
Category : Government reports announcements & index
Languages : en
Pages : 1178
Book Description
Publisher:
ISBN:
Category : Government reports announcements & index
Languages : en
Pages : 1178
Book Description
Government Reports Annual Index: Keyword A-L
Author:
Publisher:
ISBN:
Category : Government reports announcements & index
Languages : en
Pages : 976
Book Description
Publisher:
ISBN:
Category : Government reports announcements & index
Languages : en
Pages : 976
Book Description
Dye Laser Excited Fluorescence Spectroscopy of Matrix Isolated Polycyclic Aromatic Hydrocarbons
Author: Randall Robert Gore
Publisher:
ISBN:
Category : Aromatic compounds
Languages : en
Pages : 314
Book Description
Publisher:
ISBN:
Category : Aromatic compounds
Languages : en
Pages : 314
Book Description
Quenching-independent Measurement of Species Concentrations in Flames by Laser-induced Fluorescence
Author:
Publisher:
ISBN:
Category :
Languages : en
Pages : 29
Book Description
This report describes work accomplished in the last two years on measurement of species concentrations in flames via laser-induced fluorescence. During this period, we have published absolute number densities of atomic hydrogen in subatmospheric, premixed C2H4/O2/Ar flames at equivalence ratios of 1.0 and 1.7 via two-photon excited fluorescence. This work has led to the development of a new single-laser, two-step fluorescence method for the detection of atomic hydrogen in flames. Using photoionization controlled-loss spectroscopy (PICLS), we have verified the T−12 dependence of quenching on temperature for atomic hydrogen, in agreement with kinetic theory. Previous work on pyrometry using laser-saturated fluorescence (LSF) and the anomalous fluorescence from pyrene has evolved into publication of a major review paper on temperature measurements by light-scattering methods. Finally, we have demonstrated the feasibility of quantitative LSF measurements of NO concentration by obtaining relative saturation curves and NO fluorescence profiles. 25 refs.
Publisher:
ISBN:
Category :
Languages : en
Pages : 29
Book Description
This report describes work accomplished in the last two years on measurement of species concentrations in flames via laser-induced fluorescence. During this period, we have published absolute number densities of atomic hydrogen in subatmospheric, premixed C2H4/O2/Ar flames at equivalence ratios of 1.0 and 1.7 via two-photon excited fluorescence. This work has led to the development of a new single-laser, two-step fluorescence method for the detection of atomic hydrogen in flames. Using photoionization controlled-loss spectroscopy (PICLS), we have verified the T−12 dependence of quenching on temperature for atomic hydrogen, in agreement with kinetic theory. Previous work on pyrometry using laser-saturated fluorescence (LSF) and the anomalous fluorescence from pyrene has evolved into publication of a major review paper on temperature measurements by light-scattering methods. Finally, we have demonstrated the feasibility of quantitative LSF measurements of NO concentration by obtaining relative saturation curves and NO fluorescence profiles. 25 refs.
Handbook of Fluorescence Spectra of Aromatic Molecules
Author: Isadore B. Berlman
Publisher:
ISBN:
Category : Aromatic compounds
Languages : en
Pages : 288
Book Description
Publisher:
ISBN:
Category : Aromatic compounds
Languages : en
Pages : 288
Book Description
Laser-induced Fluorescence Measurements of Radical Species in Flames of Methane-nitrous Oxide and Formaldehyde-nitrous Oxide
Author: Mohammed Badr Ahmed Habeebullah
Publisher:
ISBN:
Category : Fluorescence spectroscopy
Languages : en
Pages : 436
Book Description
Publisher:
ISBN:
Category : Fluorescence spectroscopy
Languages : en
Pages : 436
Book Description