Knowledge Bank

The magnetic rotation spectrum of acrolein has been studied using an apparatus 1 m long and field strengths up to 5000 G. The effective path length was increased by a factor of 8 by the use of external multiple reflection mirrors. Five bands have been found at 4040, 4122, 4178, 4220 and 4322 \AA. The first four bands are assigned to the $\mathrm{<mrow\; data-mjx-texclass="ORD">3</mrow>}$^{\prime\prime} --- $\mathrm{<mrow\; data-mjx-texclass="ORD">1</mrow>}A$^{\prime} ($\pi \ast$ - n) system of trans acrolein with the 0-0 band at 4122 A. The fifth band at 4322 \AA is assigned as the 0-0 band of the $\mathrm{<mrow\; data-mjx-texclass="ORD">3</mrow>}A$^{\prime\prime} --- $\mathrm{<mrow\; data-mjx-texclass="ORD">1</mrow>}A$^{\prime} ($\pi \ast$ --- n) transition of the cis (or gauche) isomer. An energy level diagram showing the relative energies of the cis (or gauche) and trans isomers in the ground $\mathrm{<mrow\; data-mjx-texclass="ORD">1</mrow>}A$^{\prime} and excited $\mathrm{<mrow\; data-mjx-texclass="ORD">1</mrow>}A$^{\prime\prime} and $\mathrm{<mrow\; data-mjx-texclass="ORD">3</mrow>}A$^{\prime\prime} ($\pi \ast$ --- n) states will be shown.