Christopher Plum - Academia.edu (original) (raw)
Papers by Christopher Plum
International Journal of Chemical Kinetics, Jul 1, 1984
Rate constants have been determined at 296 ± 2 K for the gas phase reaction of NO3 radicals with ... more Rate constants have been determined at 296 ± 2 K for the gas phase reaction of NO3 radicals with a series of aromatics using a relative rate technique. The rate constants obtained (in cm3 molecule−1 s−1 units) were: benzene, <2.3 × 10−17; toluene, (1.8 ± 1.0) × 10−17; oxylene, (1.1 ± 0.5) × 10−16; mxylene, (7.1 ± 3.4) × 10−17; pxylene, (1.4 ± 0.6) × 10−16; 1,2,3‐trimethylbenzene, (5,6 ± 2.6) × 10−16; 1,2,4‐trimethylbenzene (5.4 ‐ 2.5) × 10−16; 1,3,5‐trimethylbenzene, (2.4 ± 1.1) × 10−16; phenol, (2.1 ± 0.5) × 10−12; methoxybenzene, (5.0 ± 2.8) × 10−17; o‐cresol, (1.20 ± 0.34) × 10−11; m‐cresol, (9.2 ± 2.4) × 10−12; p‐cresol, (1.27 ± 0.36) × 10−11; and benzaldehyde, (1.13 ± 0.25) × 10−15. These kinetic data, together with, in the case of phenol, product data, suggest that these reactions proceed via H‐atom abstraction from the substituent groups. The magnitude of the rate constants for the hydroxy‐substituted aromatics indicates that the nighttime reaction of NO3 radicals with these aromatics can be an important loss process for both NO3 radicals and these organics, as well as being a possible source of nitric acid, a key component of acid deposition.
Applied physics, Feb 1, 1981
The efficiency of 13 C isotope separation by multiphoton dissociation using a CO 2 laser has been... more The efficiency of 13 C isotope separation by multiphoton dissociation using a CO 2 laser has been shown to increase by ~ 33 % upon addition of small amounts of HI to the starting mixture. The reason for this increase is that the CF 3 radicals are scavenged by HI more rapidly than they recombine with free iodine atoms to reform the starting material. For Pcv3 =0.05 Torr and for 0.5 J/cm 2 roughly 65 % of the CF 3 and I radicals reform the starting material in the absence of HI. The results of this study indicate that at-80 ~ the rate constants for CF 3 + CF 3-+C2F 6 and CF 3 + I-, CF3I are about equal and are roughly 8 times higher than that for CF 3 +HI~CF3H+ I.
Geophysical Research Letters, Oct 1, 1983
The reaction of N2O5 with water vapor, a potentially important nighttime loss reaction for NOx an... more The reaction of N2O5 with water vapor, a potentially important nighttime loss reaction for NOx and formation pathway for nitric acid, has been investigated at 298 ± 1 K in two environmental chambers of 3800 and 5800 L volume. From the N2O5 decay rates as a function of water vapor concentration, an upper limit to the N2O5 + H2O rate constant of less than 2.4 × 10−21 cm³ molecule−1 s−1 is derived. However, while gas phase nitric acid was observed to be a major product, its yield, especially at low water vapor concentrations, was significantly lower than the value of 2 expected, indicating that the overall reaction in these chambers involved both homogeneous and heterogeneous components. After allowing for the contribution of the heterogeneous reaction, an estimate of the gas phase homogeneous rate constant for N2O5 + H2O of 1.3 × 10−21 cm³ molecule−1 s−1 was obtained. While this value must still be regarded as an upper limit to the homogeneous rate constant, it is a factor of 10 lower than the only directly measured upper limit reported previously.
The Journal of Physical Chemistry, Mar 1, 1984
In this work presented rate constants were determined for the gas-phase reactions of NOâ radicals... more In this work presented rate constants were determined for the gas-phase reactions of NOâ radicals with a series of organics at 298 +/- 1 K using two experimental techniques, one by monitoring the enhanced decay rates of NâOâ in the presence of a reactive organic and the other employing a relative rate technique. Rate constants for the alkenes (apart from
The Journal of Physical Chemistry, Sep 1, 1984
Page 1. 1210 J. Phys. Chem. 1984, 88, 1210-1215 Rate Constants for the Gas-Phase Reactions of Nit... more Page 1. 1210 J. Phys. Chem. 1984, 88, 1210-1215 Rate Constants for the Gas-Phase Reactions of Nitrate Radicals with a Series of Organics in Air at 298 f 1 K Roger Atkinson,* Christopher N. Plum, William PL Carter, Arthur M. Winer, and James N. Pitts, Jr. ...
Atmospheric environment, 1984
Gaseous nitrous acid in air has been simultaneously monitored in environmental chambers by an abs... more Gaseous nitrous acid in air has been simultaneously monitored in environmental chambers by an absolute method, differential optical absorption spectroscopy, and by a nylon cartridge-chemiluminence NO, technique originally developed by Spicer and co-workers for gaseous HNOJ. In the absence of HNOs, the latter technique proved to be a simple and accurate method for measuring ppb levels of HONO in air. However, the positive interference by HONO in the nylon cartridge-chemiluminescence technique may have important ramifications due to possible artifacts in measurements of gaseous HNQs by removal on nylon surfaces. Thus, previous observations in night-time atmospheres or environmental chambers attributed entirely to gaseous HNO, may have been, at least in part, due to the presence of gaseous HONO.
The Journal of Physical Chemistry, May 1, 1984
Relative rate constants for the gas-phase reactions of the NO3 radical, an important reactive spe... more Relative rate constants for the gas-phase reactions of the NO3 radical, an important reactive species observed in nighttime atmospheres, with a series of alkanes have been determined at 296 f 2 K. Using a rate constant for the reaction of NO3 radicals with ethene of (6.1 f 2.6) X cm3 m~lecule-~ d): n-butane, 2.0 f 1.0; n-pentane, 2.4 f 1.2; n-hexane, 3.2 f 1.5; n-heptane, 4.1 f 1.8; n-octane, 5.5 f 2.5; n-nonane, 1.2 f 3.3; isobutane, 2.9 f 1.4; 2,3-dimethylbutane, 12.1 f 5.4; and cyclohexane, 4.0 f 1.9. These data, which are the first to be reported for the reaction of NO3 radicals with alkanes, indicate that these reactions are a minor loss process for alkanes in the troposphere, relative to daytime hydroxyl radical attack, but that they may play a role in the formation of nitric acid, a key constituent of acid deposition, during nighttime hours in polluted atmospheres. cm3 molecule-' s-', we obtained the following rate constants (in units of
Journal of Chemical Physics, Mar 15, 1983
The probability for deactivation of CO2(001) has been found to be 0.22 for collisions with a stai... more The probability for deactivation of CO2(001) has been found to be 0.22 for collisions with a stainless steel surface, 0.16 for silver, and 0.20 for nickel. The probability for deactivation on the silver surface was invariant with surface temperature in the range from 298 to 473 K. A pulsed CO2 laser was used to excite the CO2, while the population of vibrationally excited molecules was monitored by observing their infrared fluorescence at 4.3 μm.
International Journal of Chemical Kinetics, Jul 1, 1984
The formation of nitrous acid (HONO) in the dark from initial concentrations of N0 2 of 0.1-20 pp... more The formation of nitrous acid (HONO) in the dark from initial concentrations of N0 2 of 0.1-20 ppm in air, and the concurrent disappearance of N0 2 , were monitored quantitatively by UV differential optical absorption spectroscopy in two different environmental chambers of ca.4300-and 5800-L volume (both with surface/volume ratios of 3.4 m' 1). In these environmental chambers the initial HONO formation rate was first order in the N0 2 concentration and increased with the water vapor concentration. However, the BONO formation rate was independent of the NO concentration and relatively insensitive to temperature. The initial pseudo-first-Qrder consumption rate of N0 2 was (2.8 :!: 1.2) x 10-4 min-1 in the 5800-L Tefion-coated evacuable chamber and (1.6 ± 0.5) x 10-4 min-1 in a 4300-L all•Teflon reaction chamber at ca.300 K and ca.50% RH. The initial HONO yields were ca.40-50% of the N0 2 reacted in the evacuable chamber and ca. 10-30% in the all-Tefton chamber. Nitric oxide formation was observed during the later stages of the reaction in the evacuable chamber, but ca.50% of the nitrogen could not be accounted for, and gas phase HN0 3 was not detected. The implications of these data concerning radical sources in environmental chamber irradiations of NO xorganic-air mixtures, and of HONO formation in polluted atmospheres. are discussed.
Chemischer Informationsdienst, Oct 23, 1984
Chemical Physics, 1980
ABSTRACT Infrared multiphoton dissociation of the planar ring compound has been shown to yield tw... more ABSTRACT Infrared multiphoton dissociation of the planar ring compound has been shown to yield two CF2S molecules. The threshold for dissociation using the R(16) transition of the 9.6 μm CO2 laser is 0.12 J/cm2. At fluences above 1 J/cm3 dissociation is accompanied by the emission of light in the 300–750 nm region. The fractional dissociation per pulse and the average energy deposition have been measured as functions of laser fluence, laser wavelength, C2F4S2 pressure, and added argon pressure. The variations of the fractional dissociation with fluence and absorbed energy are compared to the predictions of two models. The first model is based on the assumption of a Planck distribution for the dissociating C2F4S2 molecules, while the second is based on a rate equation approach to the dissociation. Both models predict that the dissociating parent compound has a rather broad vibrational distribution.
Canadian Journal of Chemistry, 1973
The racemization of (+)-2,3-divinyloxirane is facile at lMa, log (k,/s-l) = (11.3 + 0.5)-(30.1 +_... more The racemization of (+)-2,3-divinyloxirane is facile at lMa, log (k,/s-l) = (11.3 + 0.5)-(30.1 +_ 0.4)/0 where 0 = 2.303RT in kcal mol-'. A slower but competitive rearrangement yields racemic 2-vinyl-2,3-dihydrofuran. The mechanisms of these reactions are discussed in terms of electrocyclic processes.-La ractlnisation du (+) divinyl-2,3 oxiranne est facile a 1502, log (~, I S-~) = (11.3 + 0.5)-(30.1 _+ 0.4)/0 oh 0 = 2.303RT exprime en kcal/mol. Un rearrangement beaucoup plus lent mais cornpetitif conduit au vinyl-2 dihydro-2,3 furanne racemique. Les mecanismes de ces reactions sont discutes en termes de processus electrocycliques.
La presente invention concerne un procede informatise permettant de recuperer des donnees brutes ... more La presente invention concerne un procede informatise permettant de recuperer des donnees brutes depuis une base de donnees contenant des donnees appartenant a plusieurs enregistrements de transactions relatives a un voyage et a des documents de voyage. Les donnees brutes stockees dans la base de donnees comprennent les informations se trouvant dans le document de voyage. Un resume de l'enregistrement des transactions relatives a un voyage est fonde sur les informations contenues dans les documents d'appui. Ce procede informatise comprend les etapes consistant a recuperer les donnees brutes et a creer dynamiquement un resume de l'enregistrement des transactions relatives a un voyage concernant l'ensemble des documents associes. En outre, le procede decrit dans cette invention comprend l'etape consistant a creer dynamiquement une image documentaire d'une telle documentation d'appui au moyen des donnees brutes stockees dans la base de donnees.
Appl Phys a Mat Sci Process, 1981
Atmospheric Environment (1967), 1984
Gaseous nitrous acid in air has been simultaneously monitored in environmental chambers by an abs... more Gaseous nitrous acid in air has been simultaneously monitored in environmental chambers by an absolute method, differential optical absorption spectroscopy, and by a nylon cartridge-chemiluminence NO, technique originally developed by Spicer and co-workers for gaseous HNOJ. In the absence of HNOs, the latter technique proved to be a simple and accurate method for measuring ppb levels of HONO in air. However, the positive interference by HONO in the nylon cartridge-chemiluminescence technique may have important ramifications due to possible artifacts in measurements of gaseous HNQs by removal on nylon surfaces. Thus, previous observations in night-time atmospheres or environmental chambers attributed entirely to gaseous HNO, may have been, at least in part, due to the presence of gaseous HONO.
The Journal of Chemical Physics, 1983
ABSTRACT Typescript (photocopy) Thesis (Ph. D.)--Cornell University, Jan., 1984. Includes bibliog... more ABSTRACT Typescript (photocopy) Thesis (Ph. D.)--Cornell University, Jan., 1984. Includes bibliographical references.
International Journal of Chemical Kinetics, Jul 1, 1984
Rate constants have been determined at 296 ± 2 K for the gas phase reaction of NO3 radicals with ... more Rate constants have been determined at 296 ± 2 K for the gas phase reaction of NO3 radicals with a series of aromatics using a relative rate technique. The rate constants obtained (in cm3 molecule−1 s−1 units) were: benzene, <2.3 × 10−17; toluene, (1.8 ± 1.0) × 10−17; oxylene, (1.1 ± 0.5) × 10−16; mxylene, (7.1 ± 3.4) × 10−17; pxylene, (1.4 ± 0.6) × 10−16; 1,2,3‐trimethylbenzene, (5,6 ± 2.6) × 10−16; 1,2,4‐trimethylbenzene (5.4 ‐ 2.5) × 10−16; 1,3,5‐trimethylbenzene, (2.4 ± 1.1) × 10−16; phenol, (2.1 ± 0.5) × 10−12; methoxybenzene, (5.0 ± 2.8) × 10−17; o‐cresol, (1.20 ± 0.34) × 10−11; m‐cresol, (9.2 ± 2.4) × 10−12; p‐cresol, (1.27 ± 0.36) × 10−11; and benzaldehyde, (1.13 ± 0.25) × 10−15. These kinetic data, together with, in the case of phenol, product data, suggest that these reactions proceed via H‐atom abstraction from the substituent groups. The magnitude of the rate constants for the hydroxy‐substituted aromatics indicates that the nighttime reaction of NO3 radicals with these aromatics can be an important loss process for both NO3 radicals and these organics, as well as being a possible source of nitric acid, a key component of acid deposition.
Applied physics, Feb 1, 1981
The efficiency of 13 C isotope separation by multiphoton dissociation using a CO 2 laser has been... more The efficiency of 13 C isotope separation by multiphoton dissociation using a CO 2 laser has been shown to increase by ~ 33 % upon addition of small amounts of HI to the starting mixture. The reason for this increase is that the CF 3 radicals are scavenged by HI more rapidly than they recombine with free iodine atoms to reform the starting material. For Pcv3 =0.05 Torr and for 0.5 J/cm 2 roughly 65 % of the CF 3 and I radicals reform the starting material in the absence of HI. The results of this study indicate that at-80 ~ the rate constants for CF 3 + CF 3-+C2F 6 and CF 3 + I-, CF3I are about equal and are roughly 8 times higher than that for CF 3 +HI~CF3H+ I.
Geophysical Research Letters, Oct 1, 1983
The reaction of N2O5 with water vapor, a potentially important nighttime loss reaction for NOx an... more The reaction of N2O5 with water vapor, a potentially important nighttime loss reaction for NOx and formation pathway for nitric acid, has been investigated at 298 ± 1 K in two environmental chambers of 3800 and 5800 L volume. From the N2O5 decay rates as a function of water vapor concentration, an upper limit to the N2O5 + H2O rate constant of less than 2.4 × 10−21 cm³ molecule−1 s−1 is derived. However, while gas phase nitric acid was observed to be a major product, its yield, especially at low water vapor concentrations, was significantly lower than the value of 2 expected, indicating that the overall reaction in these chambers involved both homogeneous and heterogeneous components. After allowing for the contribution of the heterogeneous reaction, an estimate of the gas phase homogeneous rate constant for N2O5 + H2O of 1.3 × 10−21 cm³ molecule−1 s−1 was obtained. While this value must still be regarded as an upper limit to the homogeneous rate constant, it is a factor of 10 lower than the only directly measured upper limit reported previously.
The Journal of Physical Chemistry, Mar 1, 1984
In this work presented rate constants were determined for the gas-phase reactions of NOâ radicals... more In this work presented rate constants were determined for the gas-phase reactions of NOâ radicals with a series of organics at 298 +/- 1 K using two experimental techniques, one by monitoring the enhanced decay rates of NâOâ in the presence of a reactive organic and the other employing a relative rate technique. Rate constants for the alkenes (apart from
The Journal of Physical Chemistry, Sep 1, 1984
Page 1. 1210 J. Phys. Chem. 1984, 88, 1210-1215 Rate Constants for the Gas-Phase Reactions of Nit... more Page 1. 1210 J. Phys. Chem. 1984, 88, 1210-1215 Rate Constants for the Gas-Phase Reactions of Nitrate Radicals with a Series of Organics in Air at 298 f 1 K Roger Atkinson,* Christopher N. Plum, William PL Carter, Arthur M. Winer, and James N. Pitts, Jr. ...
Atmospheric environment, 1984
Gaseous nitrous acid in air has been simultaneously monitored in environmental chambers by an abs... more Gaseous nitrous acid in air has been simultaneously monitored in environmental chambers by an absolute method, differential optical absorption spectroscopy, and by a nylon cartridge-chemiluminence NO, technique originally developed by Spicer and co-workers for gaseous HNOJ. In the absence of HNOs, the latter technique proved to be a simple and accurate method for measuring ppb levels of HONO in air. However, the positive interference by HONO in the nylon cartridge-chemiluminescence technique may have important ramifications due to possible artifacts in measurements of gaseous HNQs by removal on nylon surfaces. Thus, previous observations in night-time atmospheres or environmental chambers attributed entirely to gaseous HNO, may have been, at least in part, due to the presence of gaseous HONO.
The Journal of Physical Chemistry, May 1, 1984
Relative rate constants for the gas-phase reactions of the NO3 radical, an important reactive spe... more Relative rate constants for the gas-phase reactions of the NO3 radical, an important reactive species observed in nighttime atmospheres, with a series of alkanes have been determined at 296 f 2 K. Using a rate constant for the reaction of NO3 radicals with ethene of (6.1 f 2.6) X cm3 m~lecule-~ d): n-butane, 2.0 f 1.0; n-pentane, 2.4 f 1.2; n-hexane, 3.2 f 1.5; n-heptane, 4.1 f 1.8; n-octane, 5.5 f 2.5; n-nonane, 1.2 f 3.3; isobutane, 2.9 f 1.4; 2,3-dimethylbutane, 12.1 f 5.4; and cyclohexane, 4.0 f 1.9. These data, which are the first to be reported for the reaction of NO3 radicals with alkanes, indicate that these reactions are a minor loss process for alkanes in the troposphere, relative to daytime hydroxyl radical attack, but that they may play a role in the formation of nitric acid, a key constituent of acid deposition, during nighttime hours in polluted atmospheres. cm3 molecule-' s-', we obtained the following rate constants (in units of
Journal of Chemical Physics, Mar 15, 1983
The probability for deactivation of CO2(001) has been found to be 0.22 for collisions with a stai... more The probability for deactivation of CO2(001) has been found to be 0.22 for collisions with a stainless steel surface, 0.16 for silver, and 0.20 for nickel. The probability for deactivation on the silver surface was invariant with surface temperature in the range from 298 to 473 K. A pulsed CO2 laser was used to excite the CO2, while the population of vibrationally excited molecules was monitored by observing their infrared fluorescence at 4.3 μm.
International Journal of Chemical Kinetics, Jul 1, 1984
The formation of nitrous acid (HONO) in the dark from initial concentrations of N0 2 of 0.1-20 pp... more The formation of nitrous acid (HONO) in the dark from initial concentrations of N0 2 of 0.1-20 ppm in air, and the concurrent disappearance of N0 2 , were monitored quantitatively by UV differential optical absorption spectroscopy in two different environmental chambers of ca.4300-and 5800-L volume (both with surface/volume ratios of 3.4 m' 1). In these environmental chambers the initial HONO formation rate was first order in the N0 2 concentration and increased with the water vapor concentration. However, the BONO formation rate was independent of the NO concentration and relatively insensitive to temperature. The initial pseudo-first-Qrder consumption rate of N0 2 was (2.8 :!: 1.2) x 10-4 min-1 in the 5800-L Tefion-coated evacuable chamber and (1.6 ± 0.5) x 10-4 min-1 in a 4300-L all•Teflon reaction chamber at ca.300 K and ca.50% RH. The initial HONO yields were ca.40-50% of the N0 2 reacted in the evacuable chamber and ca. 10-30% in the all-Tefton chamber. Nitric oxide formation was observed during the later stages of the reaction in the evacuable chamber, but ca.50% of the nitrogen could not be accounted for, and gas phase HN0 3 was not detected. The implications of these data concerning radical sources in environmental chamber irradiations of NO xorganic-air mixtures, and of HONO formation in polluted atmospheres. are discussed.
Chemischer Informationsdienst, Oct 23, 1984
Chemical Physics, 1980
ABSTRACT Infrared multiphoton dissociation of the planar ring compound has been shown to yield tw... more ABSTRACT Infrared multiphoton dissociation of the planar ring compound has been shown to yield two CF2S molecules. The threshold for dissociation using the R(16) transition of the 9.6 μm CO2 laser is 0.12 J/cm2. At fluences above 1 J/cm3 dissociation is accompanied by the emission of light in the 300–750 nm region. The fractional dissociation per pulse and the average energy deposition have been measured as functions of laser fluence, laser wavelength, C2F4S2 pressure, and added argon pressure. The variations of the fractional dissociation with fluence and absorbed energy are compared to the predictions of two models. The first model is based on the assumption of a Planck distribution for the dissociating C2F4S2 molecules, while the second is based on a rate equation approach to the dissociation. Both models predict that the dissociating parent compound has a rather broad vibrational distribution.
Canadian Journal of Chemistry, 1973
The racemization of (+)-2,3-divinyloxirane is facile at lMa, log (k,/s-l) = (11.3 + 0.5)-(30.1 +_... more The racemization of (+)-2,3-divinyloxirane is facile at lMa, log (k,/s-l) = (11.3 + 0.5)-(30.1 +_ 0.4)/0 where 0 = 2.303RT in kcal mol-'. A slower but competitive rearrangement yields racemic 2-vinyl-2,3-dihydrofuran. The mechanisms of these reactions are discussed in terms of electrocyclic processes.-La ractlnisation du (+) divinyl-2,3 oxiranne est facile a 1502, log (~, I S-~) = (11.3 + 0.5)-(30.1 _+ 0.4)/0 oh 0 = 2.303RT exprime en kcal/mol. Un rearrangement beaucoup plus lent mais cornpetitif conduit au vinyl-2 dihydro-2,3 furanne racemique. Les mecanismes de ces reactions sont discutes en termes de processus electrocycliques.
La presente invention concerne un procede informatise permettant de recuperer des donnees brutes ... more La presente invention concerne un procede informatise permettant de recuperer des donnees brutes depuis une base de donnees contenant des donnees appartenant a plusieurs enregistrements de transactions relatives a un voyage et a des documents de voyage. Les donnees brutes stockees dans la base de donnees comprennent les informations se trouvant dans le document de voyage. Un resume de l'enregistrement des transactions relatives a un voyage est fonde sur les informations contenues dans les documents d'appui. Ce procede informatise comprend les etapes consistant a recuperer les donnees brutes et a creer dynamiquement un resume de l'enregistrement des transactions relatives a un voyage concernant l'ensemble des documents associes. En outre, le procede decrit dans cette invention comprend l'etape consistant a creer dynamiquement une image documentaire d'une telle documentation d'appui au moyen des donnees brutes stockees dans la base de donnees.
Appl Phys a Mat Sci Process, 1981
Atmospheric Environment (1967), 1984
Gaseous nitrous acid in air has been simultaneously monitored in environmental chambers by an abs... more Gaseous nitrous acid in air has been simultaneously monitored in environmental chambers by an absolute method, differential optical absorption spectroscopy, and by a nylon cartridge-chemiluminence NO, technique originally developed by Spicer and co-workers for gaseous HNOJ. In the absence of HNOs, the latter technique proved to be a simple and accurate method for measuring ppb levels of HONO in air. However, the positive interference by HONO in the nylon cartridge-chemiluminescence technique may have important ramifications due to possible artifacts in measurements of gaseous HNQs by removal on nylon surfaces. Thus, previous observations in night-time atmospheres or environmental chambers attributed entirely to gaseous HNO, may have been, at least in part, due to the presence of gaseous HONO.
The Journal of Chemical Physics, 1983
ABSTRACT Typescript (photocopy) Thesis (Ph. D.)--Cornell University, Jan., 1984. Includes bibliog... more ABSTRACT Typescript (photocopy) Thesis (Ph. D.)--Cornell University, Jan., 1984. Includes bibliographical references.