Treated results=A05-m4bii





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[Legenda]
[Contents of the thesis]
[Comments]

Treated results = A05-m4bii

The ionic potential for the system K + Br₂ K⁺ + Br₂^- is given by a Rittner potential of the form

U_ion(R) = $\displaystyle -\frac{e^2}{R}-\frac{e^2(\alpha_{\Na^+}+\alpha_{\I^-})}{2R^4}$

$\displaystyle -\frac{2e^2\alpha_{\Na^+}\alpha_{\I^-}}{R^7}-\frac{C_\ion}{R^6}$

$\displaystyle +A_\ion\, \er^{-R/\rho_\ion}+\Delta E.$ (E1)

(a coulombic term, a screened polarization term, dipole-dipole interaction and the endothermicity ${\Delta }E$ ) and the covalent potential is given by a Van der Waals term and the repulsive term:

$\begin{displaymath}U_\cov(R)=-\frac{C_\cov}{R^6}+A_\cov\,\er^{-R/\rho_\cov}$ (E2)
with the following values :
$\begin{eqnarray*}{\Delta} E&=&3.1\ \mathrm{eV},\\ \alpha _{\zs\Br_2^-}&=&150\ ... ...10^5\ \mathrm{eV},\\ H_{12}&=&4.5\times 10^{-2}\ \mathrm{eV}, \end{eqnarray*}$
and the values
$\begin{eqnarray*}\alpha_{\zs\K^+} &=& 0.94\ \AA^3\quad (\mbox{\link{[(link type:... ...box{arbitrary})\\ \quad a &=& 5\ \AA,\quad (\mbox{arbitrary}) \end{eqnarray*}$
The resulting potential is presented in figure A05-m4bii-F1.

Figure A05-m4bii-F1: K + BR₂ ionic and covalent potential.

For a system with the potential given above, the deflection function turns out to be closed. Figure A05-m4bii-F1 represents the deflection curves for chemi-ionization scattering of K + Br₂ (CM system).

The full curves represent the classically calculated scattering angle for ``ionic'' and ``covalent'' scattering at colliding energies of 10.35 and 6.9 eV, determined using a simple classical model and measurements of the differential cross section in a molecular beam experiment. The dashed curves show the ``pure inelastic'' scattering-angle contribution to the full-line curves.

Figure A05-m4bii-F2: K + BR₂, deflection curves for chemi-ionization scattering (CM system.

[(link type: `input from'; target: interpretation m5bi]

The differential cross section calculated based on the deflection function given above has the following shape: Figure A05-m4bii-F3 represents the classically calculated determined chemi-ionization differential cross section of K + Br₂ (CM system) at colliding energies of 6.9 and 10.35 eV and convoluted with the energy spread of the velocity selector.

Figure A05-m4bii-F3: K + BR₂, classically calculated chemi-ionization differential cross section (CM system) at colliding energies of 6.9 eV and 10.35 eV.

[The figure is input from the Quantitative interpretation (link type: INPUT FROM; target: A05-m5bii]

For both energies equal units have been used on the ordinate. The dotted lines indicate the $\rho$ dependence of the slope steepness for ``covalent'' scattering. At E_i= 10.35 eV and different values of the polarizability $\alpha _{\zs\Br_2^-}$ , and the ionic-well minimum $\varepsilon$ the positions of the scattering angle for b=R_cscattering respectively the classical rainbow angle have been indicated along the abscissa. The values used in the calculations have been underlined.

U_ion(R)	=	$\displaystyle -\frac{e^2}{R}-\frac{e^2(\alpha_{\Na^+}+\alpha_{\I^-})}{2R^4}$
		$\displaystyle -\frac{2e^2\alpha_{\Na^+}\alpha_{\I^-}}{R^7}-\frac{C_\ion}{R^6}$
		$\displaystyle +A_\ion\, \er^{-R/\rho_\ion}+\Delta E.$	(E1)