Measurement electronic ground-state rotational

Leung et al. [06Leu] have measured electronic ground state rotational transitions and their nuclear electric quadrupole and magnetic hyperfine structures in the n = 0 and o = 1 vibrational states using MWFT spectroscopy. From the vibrational dependence of the fitted spectroscopic parameters their equilibrium values could be determined. 

Barker J R 1984 Direct measurement of energy transfer in rotating large molecules in the electronic ground state J. Chem. Phys. 88 11... 

Photodissociation of small polyatomic molecules is an ideal field for investigating molecular dynamics at a high level of precision. The last decade has seen an explosion of many new experimental methods which permit the study of bond fission on the basis of single quantum states. Experiments with three lasers — one to prepare the parent molecule in a particular vibrational-rotational state in the electronic ground state, one to excite the molecule into the continuum, and finally a third laser to probe the products — are quite usual today. State-specific chemistry finally has become reality. The understanding of such highly resolved measurements demands theoretical descriptions which go far beyond simple models. 

Subscripts w like in eq. (2.4) do not appear in the tabulations below. Instead, the vibrational state where the measurement took place is indicated in the first column, and holds for all parameters listed on its right. Additional state information may be included, for example the symmetiy labels A and E if methyl internal rotation coupling is present. Normally, the parameters have been determined in the electronic ground state which is not notified explicitly. 

Could we know the vibrational wave function in a given electronic and rotational state It seemed that such a question could only be answered by quantum mechanical calculations. It turned out, however, that the answer can also come from experimentation. In this experiment, three states are involved the electronic ground state (G), an electronic excited state M, in particular its vibrational state. This state will be measured, and the third electronic state of a repulsive character REP) that helps as a detector see Fig. 6.14. 

Tables in the present chapter contain in their upper part data on the spin-rotation interaction constants e q (q = Inertial axes a, b, c) and In their lower part data on the rotational constants A, B, and C. Methods of measurement, references, and remarks are the same for either constant. The quartic (A, 8 and A, 5) and sextic (O, (p) centrifugal distortion constants listed In the first table (for the electronic ground state of PHg) are defined by the A-reduced form (asymmetric reduction) of the respective Hamiltonian for spin-rotation Interaction and rotation [1 to 3]. Abbreviations used in the tables are MW for microwave absorption, EL AB for electronic absorption, LMR for laser magnetic resonance, FIR for far IR, IMF for Intermodulated fluorescence.

Reynard, Evans, and Gerry [OlRey] have measured several rotational transitions in the = 0 and = 1 vibrational states of the electronic ground state using MWFT techniques. The nuclear electric quadrupole hyperfme structures of Au and I and the magnetic hyperfme effects of I were resolved, and the following sets of parameters were obtained ... 

De Natale et al. [97DeN] have measured rotational transitions of H Br and H Br in the o = 1 state of the electronic ground state to obtain die following parameter values (all in units of MHz) ... 

The electronic ground state of this non-polar species is still of interest because classical rotationally resolving methods are difficult to apply. Bermejo et al. [02Ber] report on high-resolution rovibrational Raman spectra of Cl2, Cl2, and Cl Cl, and their spectroscopic constants for the vibrational states v = 0,1,2. Wang et al. [98Wan] have measured rotationally resolved vacuum ultraviolet REMPI detected laser spectra of the Cl2 1 <— X transition, and obtained rotational constants of levels loealized in the double-well potential of... 

Fig. 1.58 Level scheme for measurements of population distributions in rotational-vibrational levels of molecular reaction products in their electronic ground state...

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