FEMTOSECOND TIME-RESOLVED COHERENT ANTI-STOKES-RAMAN SCATTERING OF THE C-EQUIVALENT-TO-C STRETCHING IN LIQUID ALKYNES

Femtosecond time-resolved coherent anti-Stokes Raman scattering has be en observed from the C=C stretching of alkynes (monoalkylacetylenes an d dialkylacetylenes). The dephasing of the C=C stretching Of C3H7C=CH is found to be accelerated in mixtures with either proton-donors or pr oton-acceptors. The dephasing rates of the C=C stretching of monoalkyl acetylenes (CnH2n+C=CH) with relatively long alkyl chains (n greater-t han-or-equal-to 4) are nearly the same and are accelerated in mixtures with dimethylformamide regardless of the length of the alkyl chain. O n the other hand, the dephasing in dialkylacetylenes is not accelerate d in mixtures with dimethylformamide, reflecting the absence of hydrog en bonding between dialkylacetylenes and dimethylformamide.