Nuclear quadrupole hyperfine quantum beats in HCl and pyrimidine measured by the pump-probe method using REMPI/LIF detection
Physikalisch-Chemisches Institut der Universität Zürich,
Winterthurerstr. 190, 8057 Zürich, Switzerland
Revised: 22 September 1999
Published online: 13 August 2013
Coherent time resolved IR-UV double resonance spectroscopy with REMPI and/or LIF detection has been used to measure the nuclear hyperfine structure of a diatomic and a polyatomic molecule. The pump-probe technique was applied and the experimental set up was optimized to achieve highest spectral resolution. Following excitation of the HCl fundamental vibrational transition by a nanosecond IR laser pulse, the nuclear quadrupole coupling constants were determined to be MHz for H35Cl and MHz for H37Cl in the J=1 and J=2 states of the v=1 level. Nuclear (Cl) spin-rotation interaction was shown to be active with the corresponding coupling constant being MHz for H35Cl and MHz for H37Cl. For pyrimidine a C-H stretch vibration was excited and the quadrupole tensor elements for the rovibronic states and 101 of the level were found to be MHz, MHz and MHz. In this case the residual frequency error was reduced to 8 kHz. The results of these jet experiments independently confirm those from millimeter wave and microwave measurements on static gas samples.
PACS: 42.50.Md – Optical transient phenomena: quantum beats, photon echo, free-induction decay, dephasings and revivals, optical nutation, and self-induced transparency / 33.15.Pw – Fine and hyperfine structure / 33.40.+f – Multiple resonances (including double and higher-order resonance processes, such as double nuclear magnetic resonance, electron double resonance, and microwave optical double resonance)
© EDP Sciences, Società Italiana di Fisica, Springer-Verlag, 2000