An electric dipole field propagated through the space around, or in the middle of, a molecule in the direction of an acidic proton will decrease the acidity, while a dipole pointed away will increase the acidity and concomitantly elongate the X-H bond.[8] These effects can therefore help to tune the acidity/basicity of a molecule to protonate/deprotonate a specific compound, or enhance hydrogen bond-donor ability for molecular recognition or anion sensing applications.[9][10] Field effects have also been shown in substituted arenes to dominate the electrostatic potential maps, which are maps of electron density used to explain intermolecular interactions.[7]