ИСТИНА

Semiexperimental equilibrium structures (re ) of 5-methyluracil (thymine) [1] and some other derivatives of uracil [2] have been determined from the microwave (MW) rotational constants or electron diffraction (ED) data taken into account rovibrational or vibrational corrections calculated with the use of ab initio anharmonic force fields. The best estimated ab initio structures of these molecules have been derived from the results of the CCSD(T)/cc-pwCVTZ(ae) optimizations with extrapolation to the higher (quadruple-zeta) basis set at the MP2 level. A remarkable agreement between the computed and semiexperimental equilibrium structures points to high accuracy of both experiment and applied theory. References: [1] N. Vogt, J. Demaison, D.N. Ksenafontov, H.D. Rudolph, J. Mol. Struct., 2014, 1076, 483-489. [2] N. Vogt, D.N. Ksenafontov, R. Rudert, A.N. Rykov, et al., in preparation.