The stability diagram with some ions under trapping parameters used for this work

2013-09-06T00:00:00Z (GMT) by C Kyriakides B S Clarke V H S Kwong
<p><strong>Figure 1.</strong> The stability diagram with some ions under trapping parameters used for this work. The coordinates <em>a<sub>z</sub></em> and <em>q<sub>z</sub></em> are dependent on the ion's <em>m</em>/<em>q</em>, the rf potential's frequency (Ω<sub>0</sub>), amplitude (<em>V</em><sub>0</sub>) and offset (<em>U</em><sub>0</sub>) as well as the trap's length and radius (2<em>z</em><sub>0</sub> and <em>r</em><sub>0</sub>). They are given by a_{z}=\displaystyle\frac{-16qU_{0}}{m\left(r_{0}^{2}+2z_{0}^{2}\right)\Omega _{0}^{2}}\quad { \rm and \quad }q_{z}=\frac{8qV_{0}}{m\left(r_{0}^{2}+2z_{0}^{2}\right)\Omega _{0}^{2}}. The ion's <em>m</em>/<em>q</em> value is also indicated. Only ions with <em>m</em>/<em>q</em> inside the region labelled stable will remain inside the trap. The first two sets of rf amplitude, frequency and dc offset, • and ▪, respectively, are used to eliminate the unwanted ions as <em>m</em>/<em>q</em> = 1, 2 and higher are placed well outside the stable regions. The eliminated ions will affect the intensity of the stored ion of interest (<em>m</em>/<em>q</em> = 1.5). In the final (third) set,, the ion of interest now free of the unwanted ions is stored under optimum conditions.</p> <p><strong>Abstract</strong></p> <p>We report our measured values for the sum of single and double charge transfer rate coefficients between <sup>3</sup>He<sup>2 +</sup> and H<sub>2</sub>, CH<sub>4</sub>, N<sub>2</sub> and CO. Our values are 2.4 ± 0.2 <b>×</b> 10<sup>−9</sup> cm<sup>3</sup> s<sup>−1</sup> for H<sub>2</sub>, 6.3 ± 0.9 <b>×</b> 10<sup>−9</sup> cm<sup>3</sup> s<sup>−1</sup> for CH<sub>4</sub>, 4.0 ± 0.3 <b>×</b> 10<sup>−9</sup> cm<sup>3</sup> s<sup>−1</sup> for N<sub>2</sub> and 4.7 ± 0.4 <b>×</b> 10<sup>−9</sup> cm<sup>3</sup> s<sup>−1</sup> for CO. The values are obtained at equivalent temperatures of 1200–2400 K.</p>