Vibrational mode mixing in terminal acetylenes: High‐resolution infrared laser study of isolated J states

摘要: Mode–mode vibrational coupling in the acetylinic CH stretch at 3330 cm−1 of 1‐butyne and 1‐pentyne is studied via high‐resolution, direct absorption infrared spectroscopy. As our previous study propyne, mixing vibration carrying oscillator strength (the bright state) with bath multiquantum combination states dark, or background, states) manifests itself spectrum fragmentation isolated state transitions into clusters closely spaced spectral lines a ∼0.01 window about zeroth order position. In spectrum, we find an experimental density mixed 114±30 states/cm−1 compared to count prediction 90 total states/cm−1, thus quantitatively determine that all possible appear spectrum. The line spacing distribution suggests Wigner expected for quantum mechanically ergodic system. Analysis mode as function J’ shows th...