caa a22 4500 465818854 CHVBK 20180323112130.0 cr unu---uuuuu 170327e19900501xx s 000 0 eng 10.1007/BF01112865 doi (NATIONALLICENCE)springer-10.1007/BF01112865 Ab initio studies of internal rotation barriers and vibrational frequencies of (C2H2)2, (CO2)2, and C2H2-CO2 [Elektronische Daten] [Richard Bone, Nicholas Handy] We have performed large-scaleab initio calculations using second order Møller-Plesset perturbation theory (MP2) on the three van der Waals dimers formed from acetylene and carbon dioxide. Intermolecular geometrical parameters are reliably computed at this level of theory. Calculations of vibrational frequencies of the van der Waals modes, currently unobtainable by experimental means, give important information about the intermolecular potential and predict significant large-amplitude motion. Zero point energy contributions are shown to be vital in assessing the relative stability of conformations which are close in energy. Our studies suggest that the barrier to interconversion tunnelling in (CO2)2 is significantly smaller than previously inferred and is approximately the same as in (C2H2)2. The reason for the rigidity of (CO2)2 is the difference in monomer centre-of-mass separation between ground state and transition state. We also show that, in addition to the previously observedC 2v form, the collinear form of C2H2-CO2 is a local minimum on its potential energy surface. Springer-Verlag, 1990 Van der Waals dimers nationallicence Vibrational frequencies nationallicence Bone Richard University Chemical Laboratory, Lensfield Road, CB2 1EW, Cambridge, UK aut Handy Nicholas University Chemical Laboratory, Lensfield Road, CB2 1EW, Cambridge, UK aut Theoretica chimica acta Springer-Verlag 78/3(1990-05-01), 133-163 0040-5744 78:3<133 1990 78 214 https://doi.org/10.1007/BF01112865 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/BF01112865 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Bone Richard University Chemical Laboratory, Lensfield Road, CB2 1EW, Cambridge, UK aut NATIONALLICENCE 700 1- Handy Nicholas University Chemical Laboratory, Lensfield Road, CB2 1EW, Cambridge, UK aut NATIONALLICENCE 773 0- Theoretica chimica acta Springer-Verlag 78/3(1990-05-01), 133-163 0040-5744 78:3<133 1990 78 214 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer