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Demore, W. B.

Publications and source records attributed to Demore, W. B..

54 records · Page 3
All sourcesNASA NTRSDOE OSTI
NASA NTRS1974

Temperature dependence of the reactions of OH and HO2 with O3

Recent steady-state experiments involving the photolysis of O2-H2O mixtures at 1849 A conducted by DeMore (1973) have provided direct evidence for the catalytic cycle involving a reaction of ozone with OH in the first step and a reaction of ozone with HO2, which is produced in the first reaction, in the second step. The measurements of the rate constants for these reactions which had first been conducted at room temperature are now extended to the temperature range from 0 to 69 C.

Demore, W. B.↗
NASA NTRS1974

O/1 D/ production in ozone photolysis near 3100 A

Relative quantum yields of O(1 D) production in ozone photolysis from 2750 to 3340 A have been determined in the gas phase at -40 C. The O(1 D) was monitored by means of its reaction with isobutane to form isobutyl alcohol. The light source was a high pressure mercury lamp combined with a monochromator, with a bandwidth of 16 A. The results show a constant O(1 D) production below 3000 A, which is taken as unity on the basis of previous work. There is a very sharp fall-off in O(1 D) production which is centered at 3080 A. At 3130 A, O(1 D) production is not greater than 0.1.

Lin, C.-L.↗
NASA NTRS1973

O(D-1) production in ozone photolysis near 310 nm

Relative quantum yields of O(D-1)production, phi, in ozone photolysis from 275 nm to 334 nm were determined in the gas phase at 233 K. The O(D-1) was monitored by means of its reaction with isobutane to form isobutyl alcohol. The light source was a high pressure mercury lamp combined with a monochromator, with a bandwidth of 1.6 nm. The results show a constant phi below 300 nm, which is taken as unity on the basis of previous work. There is a very sharp fall-off in phi which is centered at 308 nm. At 313 nm phi is not greater than 0.1.

Lin, C.↗
NASA NTRS1973

Rate constants for the reactions of hydroxyl and hydroperoxyl radicals with ozone.

Chain decomposition of ozone by hydroxyl and hydroperoxyl radicals has been observed. The rate constant at 300 K for OH + O3 yielding HO2 + O2 is eight times ten to the -14th power cubic centimeters per second. The rate constant for HO2 + O3 yielding OH + 2O2 is three times ten to the -15th power cubic centimeters per second. These results have implications concerning stratospheric ozone.

Demore, W. B.↗
NASA NTRS1973

Reactions of O/1D/ with methane and ethane.

Mixtures of nitrous oxide and methane and mixtures of nitrous oxide and ethane were photolyzed with 1849-A light. The reaction products were analyzed chromatographically. It was found that the reaction of the excited atomic oxygen with methane gives mainly CH3 and OH radicals as initial products, along with about 9% of formaldehyde and molecular hydrogen. The reaction of the excited atomic oxygen with ethane gives C2H5, OH, CH3 and CH2OH as major initial products, with only a few per cent of molecular hydrogen.

Lin, C.-L.↗
NASA NTRS1972

Temperature and pressure dependence of CO2 extinction coefficients.

Results are presented of CO2 extinction coefficient measurements that were performed under conditions of temperature and pressure different from those used by previous investigators. The results show that, whereas pressure effects are generally negligible, temperature dependence is strong enough to invalidate the use of room temperature data for the Mars atmosphere.

Demore, W. B.↗
NASA NTRS1972

Activation energies for addition of O/3P/ to simple olefins.

Description of relative rate measurements for the addition of O(3P) to C2H4, C2F4, C3H6, and C4H8-1 in liquid argon at 87.5 K. The data strongly indicate that the activation energies for the addition of O(3P) to the double bonds of propylene and butene-1 are identical, probably to within 0.1 kcal/mole. It is very doubtful that differences in pre-exponential factors or other factors such as solvent effects, could invalidate this conclusion. A similar argument holds for the C2H4 and C2F4 reactions. Furthermore, the experiments suggest that the activation energy for addition of O(3P) to the double bond of butene-1 is about 0.1 kcal/mole.

Demore, W. B.↗
NASA NTRS1971

Photolysis of CO2 at 1849 A

Carbon dioxide photolysis at 1849 A and various pressures, suggesting gas dissociation at wavelengths with appreciable absorption

Demore, W. B.↗