These results are confirmed in the real
For a molecular liquid it is convenient to remove the intramolecular contributions by subtracting the molecular form factor F (Q) from SM (Q) to obtain the distinct structure factor:equation(2)DM(Q)=SM(Q)−F(Q)DMQ=SMQ−FQwithequation(3)FQ=∑α,β=1maαaβJ0Qrαβ×exp−Δrαβ2Q2/2/∑α=1maα2where J0(x) is the zero order spherical Bessel function and 〈Δrαβ2〉1/2 = μαβ is the root mean-square vibrational amplitude for the α-β PP242 pair. The distinct structure factor DM (Q) contains all the intermolecular contributions and usually decays to zero very rapidly. However, when hydrogen bonds exist between molecules, DM continues to oscillate in the high Q-range  and ; we therefore split DM (Q) into two parts:equation(4)DMQ=DMHBQ+DMNHBQwhereequation(5)DMHBQ=2aOaOsinQrOOQrOOexp−μOO2Q22+aHaOsinQrHOQrHOexp−μHOQ22/∑a=1maarepresents the hydrogen bond contribution of a given FA molecule linked to another one and DMNHB(Q) represents the intermolecular correlations other than the H-bonded interactions. By Fourier transformation, one calculates the intermolecular pair correlation function,equation(6)gLr=1+1/2π2ρr∫0∞QDMQsinQrdQ.