1 Raised over Fort McHenry on the morning of September 14, 1814, to signal American victory over the British in the Battle of Baltimore; the sight inspired Francis Scott Key to write The Star-Spangled Banner. 2  Preserved by the Armistead family as a memento of the battle.
London dispersion forces are a type of intermolecular force. They are relatively weak. They are also called induce-dipole induce-dipole interactions. 1  Present in non-polar molecules.  Due to non-systematic electron distribution where one molecule induces a dipole on another molecule.
London forces are present between all chemical groups, and usually represent the main part of the total interaction force in condensed matter, even though they are generally weaker than ionic bonds and hydrogen bonds.In solution dispersion force are weakend by competition with polarizable solvent molecules; the interactions are very weak between hydrocarbons but are sizeable if heteroatoms are are involved.