... 294 I EU, BIONDI, AND JOHNSEN where g(t) =exp [ns(0) (at, —txs) t s (1 —e '~'s) ]. ... more ... 294 I EU, BIONDI, AND JOHNSEN where g(t) =exp [ns(0) (at, —txs) t s (1 —e '~'s) ]. A fit of Eq. (10) to the measured electron density decay, using e& as the parameter to be determined, can be obtained provided that one has information concerning the value ofe2from other ...
International Journal of Mass Spectrometry and Ion Physics, 1973
Charge exchange cross sections for NO' in the 3A and IX+ states with the noble gases have been me... more Charge exchange cross sections for NO' in the 3A and IX+ states with the noble gases have been measured using a modified TOF spectrometer. In the case of the 3A ion the data suggest that the final state of the NO molecule is the zxcited state ("II,) while for the lower energy 'Z+ ion the ground state molecule is indicated. This is not always in conformity with the principle that for non-resonant charge exchange the final state leading to the smallest AE is favored.
International Journal of Mass Spectrometry and Ion Processes
ABSTRACT Rate coefficients and product-ion yields have been determined for ion/molecule reactions... more ABSTRACT Rate coefficients and product-ion yields have been determined for ion/molecule reactions of several atmospheric ions with dimethyl-methylphosphonate. The measurements were carried out using a selected-ion drift tube mass spectrometer. Most reactions are found to proceed by dissociative charge transfer. Those of nitric oxide ions in the electronic ground state occur by three-body association; those of hydronium ions occur by proton transfer.
... MT Leu, MA Biondi, and R. Johnsen, preceding paper, Phys. Rev. A 8, 413 (1973) [INSPEC];[CAS]... more ... MT Leu, MA Biondi, and R. Johnsen, preceding paper, Phys. Rev. A 8, 413 (1973) [INSPEC];[CAS]. MT Leu, MA Biondi, and R. Johnsen, Phys. Rev. A 7, 293 (1973). ... Phys. 56, 2802 (1967). [AG Harrison and JJ Myher, J. Chem. Phys. 46, 3276 (1967)]. ...
The rate coefficient of the reaction O + + NO - O + NO + has been measured as a function of the ... more The rate coefficient of the reaction O + + NO - O + NO + has been measured as a function of the ion kinetic energy using a drift tube-mass spectrometer apparatus. The rate coefficient decreases slowly from a value of (8.0 q- 1.2) x 10 -'3 cm3/s at 300øK to a minimum of 7 X 10 -' cm*/s at
The recombination of deuterated trihydrogen cations with electrons was studied at 80 K using stat... more The recombination of deuterated trihydrogen cations with electrons was studied at 80 K using stationary afterglow with cavity ring-down spectroscopy.
ABSTRACT We have developed a novel technique to detect the weak ionization that is produced by Re... more ABSTRACT We have developed a novel technique to detect the weak ionization that is produced by Resonance Enhanced Multiphoton Ionization (REMPI) of a small admixture of nitric oxide ( ~ milliTorr) in helium ( ~ 200Torr). In the experiment, an unfocussed beam from an excimer pumped dye laser (scanned from lambda = 226.811 to 226.955 nm) was used to ionize an NO/He mixture between two plane-parallel condenser plates. The ionization was detected by observing the small phaseshift of a radio-frequency (14.7MHz) signal that is transmitted from one plate to the other. Although the experimental setup is very simple and compact, we were able to obtain the wavelength dependence of REMPI with very high spectral resolution, sufficient to resolve rotational lines. The method may be useful for detecting gaseous impurities, as a means to calibrate the wavelength scale of lasers, and perhaps to study fast kinetic processes in plasma afterglows.
Dissociative recombination (DR) of molecular ions with electrons is a complex, poorly understood ... more Dissociative recombination (DR) of molecular ions with electrons is a complex, poorly understood molecular process. Its critical role as a neutralising agent in the Earth's upper atmosphere is now well established and its occurrence in many natural and laboratory ...
... 294 I EU, BIONDI, AND JOHNSEN where g(t) =exp [ns(0) (at, —txs) t s (1 —e '~'s) ]. ... more ... 294 I EU, BIONDI, AND JOHNSEN where g(t) =exp [ns(0) (at, —txs) t s (1 —e '~'s) ]. A fit of Eq. (10) to the measured electron density decay, using e& as the parameter to be determined, can be obtained provided that one has information concerning the value ofe2from other ...
International Journal of Mass Spectrometry and Ion Physics, 1973
Charge exchange cross sections for NO' in the 3A and IX+ states with the noble gases have been me... more Charge exchange cross sections for NO' in the 3A and IX+ states with the noble gases have been measured using a modified TOF spectrometer. In the case of the 3A ion the data suggest that the final state of the NO molecule is the zxcited state ("II,) while for the lower energy 'Z+ ion the ground state molecule is indicated. This is not always in conformity with the principle that for non-resonant charge exchange the final state leading to the smallest AE is favored.
International Journal of Mass Spectrometry and Ion Processes
ABSTRACT Rate coefficients and product-ion yields have been determined for ion/molecule reactions... more ABSTRACT Rate coefficients and product-ion yields have been determined for ion/molecule reactions of several atmospheric ions with dimethyl-methylphosphonate. The measurements were carried out using a selected-ion drift tube mass spectrometer. Most reactions are found to proceed by dissociative charge transfer. Those of nitric oxide ions in the electronic ground state occur by three-body association; those of hydronium ions occur by proton transfer.
... MT Leu, MA Biondi, and R. Johnsen, preceding paper, Phys. Rev. A 8, 413 (1973) [INSPEC];[CAS]... more ... MT Leu, MA Biondi, and R. Johnsen, preceding paper, Phys. Rev. A 8, 413 (1973) [INSPEC];[CAS]. MT Leu, MA Biondi, and R. Johnsen, Phys. Rev. A 7, 293 (1973). ... Phys. 56, 2802 (1967). [AG Harrison and JJ Myher, J. Chem. Phys. 46, 3276 (1967)]. ...
The rate coefficient of the reaction O + + NO - O + NO + has been measured as a function of the ... more The rate coefficient of the reaction O + + NO - O + NO + has been measured as a function of the ion kinetic energy using a drift tube-mass spectrometer apparatus. The rate coefficient decreases slowly from a value of (8.0 q- 1.2) x 10 -'3 cm3/s at 300øK to a minimum of 7 X 10 -' cm*/s at
The recombination of deuterated trihydrogen cations with electrons was studied at 80 K using stat... more The recombination of deuterated trihydrogen cations with electrons was studied at 80 K using stationary afterglow with cavity ring-down spectroscopy.
ABSTRACT We have developed a novel technique to detect the weak ionization that is produced by Re... more ABSTRACT We have developed a novel technique to detect the weak ionization that is produced by Resonance Enhanced Multiphoton Ionization (REMPI) of a small admixture of nitric oxide ( ~ milliTorr) in helium ( ~ 200Torr). In the experiment, an unfocussed beam from an excimer pumped dye laser (scanned from lambda = 226.811 to 226.955 nm) was used to ionize an NO/He mixture between two plane-parallel condenser plates. The ionization was detected by observing the small phaseshift of a radio-frequency (14.7MHz) signal that is transmitted from one plate to the other. Although the experimental setup is very simple and compact, we were able to obtain the wavelength dependence of REMPI with very high spectral resolution, sufficient to resolve rotational lines. The method may be useful for detecting gaseous impurities, as a means to calibrate the wavelength scale of lasers, and perhaps to study fast kinetic processes in plasma afterglows.
Dissociative recombination (DR) of molecular ions with electrons is a complex, poorly understood ... more Dissociative recombination (DR) of molecular ions with electrons is a complex, poorly understood molecular process. Its critical role as a neutralising agent in the Earth's upper atmosphere is now well established and its occurrence in many natural and laboratory ...
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Papers by Rainer Johnsen