Photochemistry of HNO/sub 3/ and ClNO/sub 3/

Technical Report · Sun Nov 01 04:00:00 EST 1981

OSTI ID:5611280

Marinelli, W J

The techniques of laser flash photolysis/resonance fluorescence (FP/RF) and flash photolysis/laser absorption (FP/LA) were used to study the reactions, (2) HO + HNO/sub 3/ ..-->.. H/sub 2/O + NO/sub 3/, (4) HO + H/sub 2/O/sub 2/ ..-->.. H/sub 2/O + HO/sub 2/, (10) Cl + HNO/sub 3/ ..-->.. products, (11) ClONO/sub 2/ + H..nu.. ..-->.. products. The results for reaction (2) are k/sub 2/ = (1.52 +- 0.43) x 10/sup -14/ exp (644 +- 79/T) cm/sup 3/ molecule/sup -1/s/sup -1/ from 218 to 363K, independent of pressure from 10 to 50 Torr Ar in the FP/RF experiments; phi/sub prod/ (NO/sub 3/ at low fluence) = 1.05 +- 0.26 with k/sub 2/ and phi/sub prod/ (NO/sub 3/) found to be pressure, concentration and fluence dependent, having a strong self-correlation in the 298K FP/LA experiments. Rate constants for reactions (4) and (10) were measured to be k/sub 4/ = (1.81 +- 0.24) x 10/sup -12/ cm/sup 3/ molecule/sup -1/s/sup -1/ and k/sub 10/ = (6.5 +- 3.4) x 10/sup -15/ cm/sup 3/ molecule/sup -1/s/sup -1/ at 298K and 10 Torr Ar; however, for (10) phi/sub prod/ (NO/sub 3/) less than or equal to 0.05. The FP/LA study of (11) found phi/sub prod/ (NO/sub 3/) = 0.55/sub -0.1//sup +0/ /sup 3/ at pressures from 20 to 100 Torr of Ar or CH/sub 4/, showing the major photodissociation channel to yield Cl and NO/sub 3/. The peak absorption cross section for the NO/sub 3/ (0,0) band was determined to be 1.9 x 10/sup -17/ cm/sup 2/ molecule/sup -1/ at 661.9 nm. The high resolution lineshape measured in this study was scaled to match integrated absorption coefficients determined in more direct but lower resolution studies. Under very high resolution (< or = 200 MHz) the band was structureless and would not fluoresce despite a lack of photodissociation. It was found to fit well to two overlapping Lorentzians in agreement with some theories of intramolecular energy transfer.

• Research Organization: Lawrence Berkeley Lab., CA (USA)
• DOE Contract Number: W-7405-ENG-48
• OSTI ID: 5611280
• Report Number(s): LBL-13473; ON: DE82005627
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
38 RADIATION CHEMISTRY, RADIOCHEMISTRY, AND NUCLEAR CHEMISTRY
400500* -- Photochemistry
400600 -- Radiation Chemistry
ABSORPTION SPECTROSCOPY
CHALCOGENIDES
CHEMICAL REACTION KINETICS
CHEMICAL REACTIONS
CHLORINE
CHLORINE COMPOUNDS
CHLORINE OXIDES
DECOMPOSITION
DYE LASERS
ELEMENTS
EMISSION SPECTROSCOPY
FLUORESCENCE SPECTROSCOPY
HALOGEN COMPOUNDS
HALOGENS
HYDROGEN COMPOUNDS
HYDROGEN PEROXIDE
HYDROXYL RADICALS
INORGANIC ACIDS
KINETICS
LASER SPECTROSCOPY
LASERS
LIQUID LASERS
NITRIC ACID
NITROGEN COMPOUNDS
NITROGEN OXIDES
NONMETALS
OXIDES
OXYGEN COMPOUNDS
PEROXIDES
PHOTOCHEMICAL REACTIONS
PHOTOLYSIS
RADICALS
REACTION KINETICS
SPECTROSCOPY