Marcin Gronowski

Computational Chemistry


Posts Tagged ‘isomers’

C5N− anion and new carbenic isomers of cyanodiacetylene: A matrix isolation IR study

Products of the vacuum-UV photolysis of cyanodiacetylene HC5N in solid argon —the anion C5N−, imine HNC5, and the branched carbene C4(H)CN —have been identified by IR absorption spectroscopy, in addition to the already discovered isonitrile HC4NC. Spectral assignments were assisted by deuterium substitution experiments, by BD(T) calculations, and by the results of a recent density functional theory study.
Full text: J. Chem. Phys. 128 (2008) 154303

Spectroscopy of cyanodiacetylene in solid argon and the photochemical generation of isocyanodiacetylene

Following the measurements of UV and mid-IR spectra of cyanodiacetylene, H-CC2-CN, isolated in low temperature Ar matrices, the first photochemical study on this compound and on its 2H isotopomer was carried out with the laser light tuned to 267 nm and with far-UV discharge lamps. Evidence for the formation of isocyanodiacetylene, H-CC2-CN, was found in infrared absorption spectra interpreted with the aid of available theoretical predictions.
Full text: J. Chem. Phys. 126 (2007) 164301

Isomers of cyanodiacetylene: Predictions for the rotational, infrared and Raman spectroscopy

Recent ab initio (coupled-clusters) and density functional theory studies on cyanodiacetylene isomers are extended here to yield the quantities of direct interest to future spectroscopic investigations. A bond lengths scaling procedure was developed to obtain the corrected molecular geometries. These, together with calculated vibration–rotation coupling constants, yielded the ground-level rotational constants for seven most stable isomeric species of the HC5N stoichiometry. Former calculations regarding the vibrational transitions of these molecules are complemented here with predictions on Raman scattering activities, and on isotopic (2H, 15N) effects in IR absorption and Raman spectra.
Full text: J. Mol. Struct. 834-836 (2007) 102

Isomers of cyanodiacetylene: Theoretical structures and IR spectra

Coupled-clusters CCSD(T)/cc-pVTZ calculations have been carried out on several lowest energy isomers of cyanodiacetylene H–CC–CC–CN, previously selected in an extensive DFT study. Apart from the izonitrile H–CC–CC–NC, branched species CC(H)CCCN and CCCC(H)CN are found to be of particular importance, less stable than cyanodiacetylene by 48.5 and 51.0 kcal/mol, respectively. Harmonic frequencies and IR absorption intensities of vibrational fundamentals were predicted at the B3LYP/aug-cc-pVTZ level.
Full text: Chem. Phys. Lett. 428 (2006) 245