Femtosecond degenerate four-wave mixing of pyridine and its biologically relevant derivatives

Abstract

Time-resolved degenerate four-wave mixing experiments in the femtosecond time domain were employed to record the rotational ground-state dynamics of the N-heteroaromatic molecules pyridine, pyrimidine and pyrazine in the gas phase. Pyrimidine is an important molecular building block of several nucleic acid bases. The method records the time-dependent change in third-order polarization of a sample after coherent excitation. All three molecules are asymmetric tops in the oblate limit. From the analysis of the transients we obtained highly accurate averages of the two larger ground-state rotational constants A and B. Copyright © 2002 John Wiley & Sons, Ltd.