def _format_collider_string(colliders):
    """ Write the string for the bath gas collider and their efficiencies
        for the Lindemann and Troe functional expressions:

        :param colliders: the {collider: efficiency} dct
        :type colliders: dct {str: float}
        :return: collider_str: Chemkin string with colliders and efficiencies
        :rtype: str
    """
    collider_str = '    '  # name_buffer
    collider_str += ''.join(
        ('{0:s}/{1:4.3f}/   '.format(collider, efficiency)
         for collider, efficiency in colliders.items()))
    collider_str += '\n'

    return collider_str