Ionization energy noble gases

Typical ion sources employ a noble gas (usually Ar). The ionization process works either by electron impact or within a plasma created by a discharge the ions are then extracted from the region in which they are created. The ions are then accelerated and focused with two or more electrostatic lenses. These ion guns are normally operated to produce ions of 0.5-10 keV energy at currents between 1 and 10 pA (or, for a duoplasmatron, up to 20 pA). The chosen spot size varies between 100 pm and 5 mm in diameter. 

Until about 40 years ago, these elements were referred to as "inert gases" they were believed to be entirely unreactive toward other substances. In 1962 Neil Bartlett, a 29-year-old chemist at the University of British Columbia, shook up the world of chemistry by preparing the first noble-gas compound. In the course of his research on platinum-fluorine compounds, he isolated a reddish solid that he showed to be 02+(PtFB-). Bartlett realized that the ionization energy of Xe (1170 kJ/mol) is virtually identical to that of the 02 molecule (1165 kJ/mol). This encouraged him to attempt to make the analogous compound XePtF6. His success opened up a new era in noble-gas chemistry. 

The difference in the ionization potentials of xenon and krypton (1170 versus 1351 kj/mol) indicates that krypton should be the less the reactive of the two. Some indication of the difference can be seen from the bond energies, which are 133 kj/mol for the Xe-F bond but only 50 kj/mol for the Kr-F bond. As a result, XeF2 is considerably more stable of the difluorides, and KrF2 is much more reactive. Krypton difluoride has been prepared from the elements, but only at low temperature using electric discharge. When irradiated with ultraviolet light, a mixture of liquid krypton and fluorine reacts to produce KF2. As expected, radon difluoride can be obtained, but because all isotopes of radon undergo rapid decay, there is not much interest in the compound. In this survey of noble gas chemistry, the... 

Emission spectra of radical cations are obtained by vacuum UV ionization and subsequent laser excitation in noble-gas matrices (see below), or by electron-impact ionization of a beam of neutral parent molecules at energies above the first ionic excited state. After internal conversion to the first excited state, emission may compete more or less successfully with radiationless deactivation. If the experiment is carried out on a supersonic molecular beam one obtains highly resolved emission spectra which, in the case of small molecules, may contain sufficient information to allow a determination of the molecular structure. 

Penning ionization occurs with the (trace) gas M having an ionization energy lower than the energy of the metastable state of the excited (noble gas) atoms A. The above ionization processes have also been employed to construct mass spectrometer ion sources. [21,24] However, Penning ionization sources never escaped the realm of academic research to find widespread analytical application. 

The rf energy is provided to the electrons, so that the rf field accelerates the electrons, which ionize the noble gas (e.g., argon) used for transporting the nebulized aerosols via electron ionization... 

The enthalpy of atomization of copper does not differ at all for the two compounds, and the atomization of chlorine adds only a small difference for the second mole of chlorine. The major energy cost for CuCl2 is the second ionization energy of copper which is compensated by the electron affinity to form the second chloride ion and especially the lattice energy. Since the electron ionized to form Cu2 is a d electron and does not break a noble gas structure, IE2 is not excessive, and both CuCl and CuCl2 are stable compounds. 

The interactions between metastable noble-gas atoms and ground-state noble-gas atoms are relatively simple and have been investigated quite extensively. If the excitation energy is lower than the ionization potential of the collision partner, the only important inelastic process is the transfer of excitation energy.12 The excitation transfer is usually very efficient when the process is near resonant. The process that is responsible for the operation of the He-Ne laser,13... 

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