Double resonance optical

The optical-optical double resonance technique was applied to determine which mechanism is predominant in the pumping of TPPZn (27, 28). Because of the large difference in the lifetimes of and T ... 

S2 - Sq fluorescence and radiationless transitions from the state of porphyrins have been studied in order to reveal photodynaunics of porphyrins. The S2 state fluorescence of zinc(II)-tetraphenylporphin is caused even by the excitation to the state. Two-photon absorption and optical-optical double resonance studies show that a stepwise two-photon absorption through the state is a main process populating the S2 state. 

K. Yamanouchi Recently, we investigated the interatomic potential VRyd(/ ) of the Rydberg states of a HgNe van der Waals dimer by optical-optical double-resonance spectroscopy. It was demonstrated that VRyd(/ ) sensitively varies as a function of the principal quantum number n [J. Chem. Phys., 98, 2675 (1993) ibid., 101, 7290 (1995) ibid., 102, 1129 (1995)], and in the lowest Rydberg states of Hg(7 3S )Ne and Hg(7 5o)Ne, the interatomic potentials exhibit a distinct barrier at around R 4 A. The existence of the barrier was interpreted in terms of a repulsive interaction caused by the Is Rydberg... 

Silvers S.J., Gottscho, R.A. and Field, R.W. (1981). Collisional depolarization of state selected (J,Mj) BaO A1S+ measured by optical-optical double resonance, J. Chem. Phys., 74, 6000-6008. 

Fig. 2. Excitation spectrum of the 1/S o —> 3 Po resonance of a single indium ion obtained in optical-optical double resonance using electron shelving. The linewidth of the fitted lorentzian is 170 Hz FWHM. The average excitation probability in the peak is about 10% and the total measuring time was 30 minutes...

Optical-optical double-resonance utilizing quantum amplification - was used to detect transitions of the ion driven by the 281.5 nm laser to the metastable 5/2 state. This method makes use of the fact that the 194 nm fluorescence intensity level is bistable high when the ion is cycling between the S and P states (the "on" state) and nearly zero when it is in the metastable D state (the "off" state). The fluorescence intensity in the on state is high enough that the state of the atom can be determined in a few milliseconds with nearly 100% efficiency. The full measurement cycle was as follows A series of measurements of the 194 nm fluorescence was made, using... 

In this chapter we are concerned with the excited triplet states. The c 3 nu state is the subject of this section, whilst the d and k 3nu states will appear later when we discuss microwave/optical double resonance studies. These triplet states are metastable,... 

We now describe briefly the FIR laser magnetic resonance studies of the four molecules listed above. FeH has also been studied by mid-infrared laser magnetic resonance, and NiH by microwave/optical double resonance these investigations are discussed elsewhere. 

The NiH radical has been studied quite thoroughly, by FIR laser magnetic resonance as described here [76], but also by microwave/optical double resonance and by mid-... 

The effective Hamiltonian and analysis of the spectra is described in chapter 11 when we discuss the microwave/optical double resonance spectrum. 

Figure 11.1. (a) Principles of the microwave/optical double resonance method, (b) Change of polarisation of fluorescent light resulting from AM= 1 radiofrequency transitions. 

Radiofrequency/optical double resonance of CS in its excited A state... 

The first radiofrequency/optical double resonance studies of molecules were published almost simultaneously. Observations of OH and OD were described by German and Zare [10] late in 1969, and will be discussed in detail in the next subsection. A few months later studies of the CS molecule in its excited A 1 n were reported by Silvers, Bergeman and Klemperer [11], with more detailed results described later by Field and Bergeman [12], We now describe these investigations, which are in some ways simpler than those of OH because of the absence of electron and nuclear spin effects in the CS 1n state. 

Figure 11.5. Ground and excited state levels involved in the radiofrequency/optical double resonance study of CS in its A 1 n state [12].

Early radiofrequency or microwave/optical double resonance studies [1 877... 

Figure 11.7. (a) Radiofrequency/optical double resonance line observed for the A -doublet transition in the J = 8 level of the A ll state ofCS. The Stark field was zero [11], (b) Radiofrequency/ optical double resonance with a Stark field, showing the M = 8 and 7 resonances for J = 8. The frequency was fixed at 1124.4 MHz while the electric field was swept. 

Figure 11.8. Hyperfine levels in OH and OD in the excited A2E+ state studied by radio frequency/ optical double resonance. The splittings are not to scale.

Figure 11.10. Principles of microwave/optical double resonance, permitting the observation of rotational transitions in either the ground or excited electronic state [16]. The ground state levels are in thermal equilibrium with the heat bath, and it is assumed that when the molecule in the excited state spontaneously emits a photon, it enters the heat bath rather than returning to the optically-depleted ground state level.

The studies of BaO were important pioneering experiments showing the power of microwave/optical double resonance methods. We shall describe a number of significant applications of these methods later in this chapter. 

In chapter 8 we described the elegant studies of Lichten [18] on the electronically excited c 3nu state of H2. Lichten s experiments involved electronic excitation of a beam of H2 molecules by collision with an electron beam, but they were not double resonance experiments. Rather, they were classic molecular beam magnetic resonance studies of the type described extensively in chapter 8. In this section we discuss later experiments on H2, again electronically excited by collision with electrons, but involving microwave/optical double resonance studies. Before we describe these experiments, however, we summarise the relevant excited states of H2, repeating to some extent our discussion in chapter 8. 

Radiofrequency or microwave/optical double resonance of alkaline earth molecules... 

Microwave/optical double resonance studies have been described for SrF by Domaille, Steimle and Harris [38], for CaCl by Domaille, Steimle and Harris [39], and for CaF by... 

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