Knowledge Bank

By means of Doppler-free polarization spectroscopy using a tunable single-mode dye laser we have investigated the hyperfine splitting of various absorption lines of molecular iodine with wavenumbers between 12620 and $13890cm-1$ due to the transition $B\mathrm{<mrow\; data-mjx-texclass="ORD">3</mrow>}\Pi u\leftarrow x\mathrm{<mrow\; data-mjx-texclass="ORD">1</mrow>}\Sigma g\mathrm{<mrow\; data-mjx-texclass="ORD">+</mrow>}$. In order to get a sufficient population of vibrational levels $v\prime \prime =10\dots 13$ of the X state the iodine absorption cell was heated to about $430\circ C$ the iodine vapor pressure being fixed to about 0.7 Torr by a cold side-finger of the cell. 15 and 21 hfs components have been observed for even and odd rotational quantum number of the X state resp. The linewidth of a single hfs component was about 15 MHZ. Despite of a partial overlapping of hfs components in most line patterns we were able to determine the center frequencies of all 15 or 21 hfs components with an accuracy of typically 2 MHz. The observed hfs patterns could fully be explained by a simple model with the two parameters $△(eQq)$ of the difference in electrical quadrupole coupling and $△c$ of the difference between effective magnetic dipole interaction. Values of $△(eQq)$ and $△c$ have been determined for vibrational transitions $v\prime -v\prime \prime$ with $v\prime =0,1,2$ and $v\prime \prime =10\dots 15$. As an example we have obtained the following result for the transition $v\prime -=2-v\prime \prime =10$ as a mean value over 14 rotational lines: $△(eQq)=(1958\pm 2)MHz$ and $△C=(24\pm 3)KHz$. In addition, the absolute wavenumbers of the o-component of 17 rotational transitions with even rotational quantum number have been determined with an accuracy of $0.001cm-1/1/$