Stark quantum beat spectroscopy of polyatomic molecules

Abstract

Abstract. We derive analytical expressions for Stark quantum beat signals of polyatomic molecules and discuss them with regard to molecular and geometrical parameters. The general treatment is specified for near prolate asymmetric rotor molecules and a method for determining rotational constants and all components of the dipole moment of electronically excited polyatomic molecules is presented. The method is tested and illustrated for the vibrationless S t state of deuterated propynal (HC=CCDO, Cs symmetry) and its lowest frequency non-totally symmetric state 121 . The results of the vibrationless state are compared with structural data reported in the literature. For the 121 state we obtain A = 1.5004(43) cm-1 B=0.16131(34) cm-1, C = 0.t4623 (34) cm-1, and the components of the electric dipole moment in the molecular plane #, = -0.88 (2) D, #b = 1.03 (2) D. Furthermore, it is shown that the modulation depth of Stark quantum beat signals can be utilized to quantify the contribution of the individual components of the transition moment to the total emission.

Quantum beat spectroscopy in chemistry

“…Furthermore in the case of nonlinear interactions, as for the Stark effect, the beat frequencies are very sensitive to the rotational constants and provide a method to refine the values obtained from conventional spectroscopic methods and hence obtain a more accurate structure. 15 In order to prepare Zeeman or Stark coherences, states of different M must be coherently excited. Normally an experimental geometry is chosen in which the excitation (and detection) polarisation is perpendicular to the external field.…”

The Stark Quantum Beat of Ne Fluorescence in the Vacuum Ultra Violet Region

“…Stark beat studies for hydrogen [13][14][15], alkali metal [16][17][18] and highly charged carbon [19] were performed with beam foil excitation. The atom polarizabilities [20,21] and molecule electronic dipole moments [22][23][24][25][26] have been investigated by analysis of electric field dependence of the beat frequency using pulsed laser excitation. Recently, Ar Rydberg state SQB was observed in VUV fluorescence using synchrotron radiation [27].…”