\documentclass{scrartcl}
\usepackage{color}
\usepackage{multicol}
\usepackage[final]{graphicx}
\usepackage{pst-plot,pstricks}
	\input{pstplot-logarithmic-axes}
\begin{document}
	\psset{xunit=3cm,yunit=4cm}
	\begin{pspicture}(-2.5,-0.7)(2.5,0.7)
		\psgrid[xunit=1,yunit=0.1,subgriddiv=0,griddots=5,gridlabels=0](-2,-7)(2,7)
		\psaxes[log=x,Dy=0.25]{->}(-2,0)(-2,-0.7)(2.2,0.7)
		\psplot[plotstyle=curve,linecolor=green]{-2}{2}{-0.5}
		\rput(2.2,0.1){$\Omega=\frac{\omega}{\omega_0}$}
		\rput(-2.2,0.65){$\frac{\Theta}{\pi}$}
	\end{pspicture}
\end{document}
