@staticmethod
def parse_line(line):
    """
        Parse line inputs.

        **Parameters**

            line: *str*
                A string that holds LJ information.

        **Returns**

            index: *str*
                The label in the line corresponding to atom type.
            sigma: *float*
                The position where the potential well equals 0.
            epsilon: *float*
                The depth of the well.
        """
    line = line.strip().split()
    index = line[0]
    sigma = float(line[1])
    epsilon = float(line[2])
    return index, sigma, epsilon
