#NEWLINE# def relaxation_frequency_oxygen( pressure , h , reference_pressure = REFERENCE_PRESSURE ) : #NEWLINE# #INDENT# '\n    Relaxation frequency of oxygen :math:`f_{r,O}`.\n    \n    :param pressure: Ambient pressure :math:`p_a`\n    :param reference_pressure: Reference pressure :math:`p_r`\n    :param h: Molar concentration of water vapour :math:`h`\n    \n    The relaxation frequency of oxygen is calculated using\n    \n    .. math:: f_{r,O} = \\frac{p_a}{p_r} \\left( 24 + 4.04 \\cdot 10^4 h \\frac{0.02 + h}{0.391 + h}  \\right)\n    \n    ' #NEWLINE# return ( ( pressure / reference_pressure ) * ( 24.0 + ( ( ( ( 4.04 * ( 10.0 ** 4.0 ) ) * h ) * ( 0.02 + h ) ) / ( 0.391 + reference_pressure ) ) ) )