@property<EOL><INDENT>def JTg(self):<DEDENT>
Vmg, Cpgm, isobaric_expansion_g = self.Vmg, self.Cpgm, self.isobaric_expansion_g<EOL>if all((Vmg, Cpgm, isobaric_expansion_g)):<EOL><INDENT>return Joule_Thomson(T=self.T, V=Vmg, Cp=Cpgm, beta=isobaric_expansion_g)<EOL><DEDENT>return None<EOL>
r'''Joule Thomson coefficient of the gas phase of the mixture if one
        exists at its current temperature and pressure, in units of [K/Pa].

        .. math::
            \mu_{JT} = \left(\frac{\partial T}{\partial P}\right)_H = \frac{1}{C_p}
            \left[T \left(\frac{\partial V}{\partial T}\right)_P - V\right]
            = \frac{V}{C_p}\left(\beta T-1\right)

        Examples
        --------
        >>> Mixture(['dodecane'], ws=[1], T=400, P=1000).JTg
        5.4089897835384913e-05