Spectroscopy of methylcyanodiacetylene revisited. Solid parahydrogen and solid neon matrix studies

Abstract Electronic phosphorescence and infrared absorption spectra of methylcyanodiacetylene (CH3C5N) are revisited using matrix isolation in solid parahydrogen and neon. Band assignments previously found for Ar, Kr, Xe, and N2 low-temperature host media were updated, with certain ambiguous attributions being resolved. A combined analysis of both dispersed phosphorescence and phosphorescence excitation spectra observed in different environments provides a means to estimate the singlet-triplet separation for the gas-phase and pure solid compound, where phosphorescence could not be observed.