@property<EOL><INDENT>def atom_fractions(self):<DEDENT>
things = dict()<EOL>for zi, atoms in zip(self.zs, self.atomss):<EOL><INDENT>for atom, count in atoms.iteritems():<EOL><INDENT>if atom in things:<EOL><INDENT>things[atom] += zi*count<EOL><DEDENT>else:<EOL><INDENT>things[atom] = zi*count<EOL><DEDENT><DEDENT><DEDENT>tot = sum(things.values())<EOL>return {atom : value/tot for atom, value in things.iteritems()}<EOL>
r'''Dictionary of atomic fractions for each atom in the mixture.

        Examples
        --------
        >>> Mixture(['CO2', 'O2'], zs=[0.5, 0.5]).atom_fractions
        {'C': 0.2, 'O': 0.8}