Structural analysis of liquid 1,4-dimethylbenzene at 293 K

Structural analysis of liquid 1,4-dimethylbenzene C6H4(CH3)2 by X-ray monochromatic radiation scattering method was performed. The X-ray measurements were made at room temperature for the scattering angle range Θ   varying from 3 to 60°. The most probable parameters of 1,4-dimethylbenzene molecules were determined from the detailed analysis of the distributions of scattered X-radiation intensity. Experimental function i(S)=[Ieu(S)−N∑jnnjfj2(S)]/Nfe2(S) was determined by X-ray scattering from a liquid sample and compared with the theoretical function im(S)   calculated for the most probable assumed model of the 1,4-dimethylbenzene structure. The theoretical and experimental curves were in good agreement, thus confirming the proposed structure of this molecule. The radial distribution function of electron density 4πr2∑j,knK¯j[ρk(r)−ρ0] was calculated according to Warren and some intra- and intermolecular distances in liquid 1,4-dimethylbenzene were determined. From the position of the main maximum in the scattered radiation intensity distribution the mean of the least intermolecular distance R¯ was calculated, to find the volume V¯ of the unit cell of liquid 1,4-dimethylbenzene. The structural data obtainable by X-ray analysis for the liquid studied were discussed.