# Is there any molecule describable by three-level with mixed parity and transition dipole moments in different directions?

I would like to know if there are molecules described by a three-level system with mixed parity and transition dipole moments in different directions. By mixed parity I mean all three transitions can be excited by electric field. In principle I don't think such a system is forbidden, but it would be perfect if there are some examples. Does anyone have an idea? Thanks!

• Should it be possible to "store it in a bottle" or are you allowing vacuum, ion traps... – mcocdawc Apr 10 '17 at 15:36
• Rotational levels in asymmetric top molecules have so-called $a$-type, $b$-type and $c$-type transitions that are associated with the different dipole moments along the $a$, $b$ and $c$ axis in the molecular-fixed frame. Of course not a "true" 3-levels system, but it depending on the rotational constants, it might be close enough. – Paul Apr 10 '17 at 16:22
• @mcocdawc For my case I prefer solid state systems. But it is still interesting to know how ion traps work. Thanks! – Pu Zhang Apr 10 '17 at 22:07
• @Paul Thanks! I think top molecules work for my question :p. – Pu Zhang Apr 10 '17 at 22:16