science-softCon uv/vis+ photochemistry database;	www.photochemistry.org; (C) science-softCon 2019

Substance: nitrous acid					Other Names: 

Formula: HONO						CAS-No.: 7782-77-6

Study: uv absorption spectra, photolysis, quantum yields


Authors: M. Fischer, P. Warneck

Title: Photodecomposition of Nitrite and Undissociated Nitrous Acid in Aqueous Solution

Journal/Source: J. Phys. Chem., 100 (48), 18749-18756, (1996); DOI: 10.1021/jp961692+


Data: table, diagram

Energy/Wavelength range: 280 - 390 nm

Resolution: 

Temperature: 295 K

Temperature dependence: 

Pressure/Concentration: 

Phase: aqueous solution (pH 2 solution)

pH:

Comments: Quantum yields of phenol and nitrate, produced by photodecomposition in aqueous solutions of NO2-  and HNO2 in 
the presence of benzene as scavenger for OH radicals, have been determined as a function of wavelength between 280 and 390 nm. 
The production of phenol was used to calculate primary OH quantum yields. For NO2- photolysis at pH 6 PHI1(OH) was found to 
decrease with increasing wavelength from 0.069 ± 0.008 at 280 nm to 0.022 ± 0.004 at 390 nm, in agreement with previous data. 
The OH quantum yield PHI2(OH) for the photolysis of HNO2  at pH 2 was essentially constant over the entire wavelength range 
with PHI2  = 0.35 ± 0.02.
The absorption maxima were found: 
HNO2 at 346.5 nm, 357 nm, 371 nm, and 385.5 nm, epsilon = 2.88, 4.07, 4.26, and 2.50 m2 mol-1.

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