Hasdeo and coworkers are giving, in their Eq.( ), the BWF line shape composed by three terms: "a constant continuum spectrum, a discrete Lorentzian spectrum, and an interference effect between both spectra". The interference term is producing the asymmetry of the profile, according to the positive and negative values of argument (x-xo). The dimensionless ξ parameter is "mimicking the ratio between the probability amplitude of the continuum spectra to that of the discrete spectra" .