Radiative lifetimes of nitrogen dioxide for excitation wavelengths from 400 to 750 nm

Journal Article · Thu Oct 04 04:00:00 EDT 1990 · Journal of Physical Chemistry; (United States)

DOI:https://doi.org/10.1021/j100383a039· OSTI ID:5359287

Patten, Jr, K O; Burley, J D; Johnston, H S ^[1]

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1. Lawrence Berkeley Laboratory, CA (USA)

At room temperature, the radiative lifetimes of nitrogen dioxide excited by pulsed, tunable, dye laser radiation are measured in a 50-L flask, for excitation wavelengths ranging from 400 to 750 nm, at total pressures between 0.25 and 2.0 mTorr, and for times between 0.7 and 60 {mu}s. The data are analyzed in terms of the Stern-Volmer mechanism to give zero-pressure radiative constants (k{sub 0} = 1/{tau}{sub 0}) and empirical collisional quenching rate constants k{sub q} by ground-state nitrogen dioxide. (a) The observed radiative coefficients generally increase linearly with increasing excitation energy (cm{sup {minus}1}): k{sub 0}/s{sup {minus}1} = 0.504(E-E{sub 0}) + 7.96 {times} 10{sup 3}, where E is the excitation energy and E{sub 0} is the energy of the origin of the {sup 2}B{sub 2} excited state. At wavelengths above about 540 nm there are strong state-to-state variations of radiative lifetime, producing large apparent scatter in the data. The zero-pressure radiative lifetimes {tau}{sub 0} are compared to previous measurements and are in rough agreement with a number of earlier studies. (b) On the other hand, different investigators typically obtain different numerical values for the Stern-Volmer collisional quenching rate constants. As observed here, the quenching rate constants k{sub q} are found to vary by almost a factor of 6 as filters are changed in front of the photomultiplier tube with all other experimental conditions held constant. Some of the difficulties of observing meaningful quenching rate constants for nitrogen dioxide are discussed.

• OSTI ID: 5359287
• Journal Information: Journal of Physical Chemistry; (United States), Journal Name: Journal of Physical Chemistry; (United States) Vol. 94:20; ISSN 0022-3654; ISSN JPCHA
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400102* -- Chemical & Spectral Procedures
CALCULATION METHODS
CHALCOGENIDES
ELECTROMAGNETIC RADIATION
EMISSION SPECTROSCOPY
ENERGY LEVELS
EXCITED STATES
FLUORESCENCE SPECTROSCOPY
LASER RADIATION
LIFETIME
MEDIUM TEMPERATURE
NITROGEN COMPOUNDS
NITROGEN DIOXIDE
NITROGEN OXIDES
OXIDES
OXYGEN COMPOUNDS
QUENCHING
RADIATIONS
SPECTROSCOPY