Optical double resonance spectroscopies

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... 

For transitions between sublevels in the ground state, the radiative lifetimes may be extremely long and the linewidth is only limited by the transit time of the molecules through the RF field. Sub-kilohertz resonances have been observed in the RF-optical double resonance spectroscopy of rare-earth ions [519]. 

R.A. Bemheim, L.P. Gold, T. Tipton, Rydberg states of Li2 by pulsed optical-optical double resonance spectroscopy. J. Chem. Phys. 78, 3635 (1983) ... 

R. Bombach, B. HemmerUng, W. Demtroder, Measurement of broadening rates, shifts and effective lifetimes of Li2 Rydbeig levels by optical double-resonance spectroscopy. Chem. Phys. 121, 439 (1988)... 

Tsai, C.-C., Bahns, J.T., Whang, T.J., Wang, H., Stwalley, W.C., and Lyyra, A.M., Optical-optical double resonance spectroscopy of the X) shelf states and ft states of Na2 using an ultrasensitive ionization detector, Phys. Rev. Lett., 71,1152,1993. 

MW optical double resonance spectroscopy. Authors identification. 

G. Gerber and R. MoUer, Optical-Optical Double Resonance Spectroscopy of High Vibrational Levels of the Na2 A State in a Molecular Beam , Chem. Phys. Lett. 113, 546 (1984). 

Optical-Optical Double-Resonance Spectroscopy in Molecular Beams... 

R.W. Field, A.D. English, T. Tanaka, D.O. Harris, P.A. Jennings Microwave optical double resonance spectroscopy with a cw dye laser ... 

R.A. Gottscho, P.S. Weiss, R.W. Field, Sub-Doppler Optical-Optical Double Resonance Spectroscopy of BaO, J. Mol. Spectrosc. 82 283 (1980). 

An important development in microwave/optical double resonance, called microwave/optical polarisation spectroscopy, was described by Ernst and Torring [42], The principles of this technique are illustrated in figure 11.22. A linearly polarised probe beam from a tunable laser is sent through the gas sample and a nearly crossed linear polariser, before its final detection. Polarised microwave radiation resonant with a rotational transition in the gas sample is introduced via a microwave horn as shown, and resonant absorption results in a partial change in polarisation of... 

There are several other interesting topics in quantum optics which we would like to be able to study. For example, we would like model problems in double resonance spectroscopy, where there are two electromagnetic fields with possibly different polarizations simultaneously interacting with a molecule. This problem resembles the multiple photon excitation problem in that there is population migration along ladders of states, but in this case there can be a vastly larger number of quantum levels to treat — on the order of 2(2J+1). At room temperature, the most probable value of J for SF is about 60, which implies a 250 state calculation. 

Questions of linkage are posed and answered by asking the molecule to satisfy successively two resonance conditions. Schemes which accomplish this include Dispersed Fluorescence Spectroscopy (DF, Section 1.2.2.2 a laser is tuned to excite a single line and the spectrum of the resulting molecular fluorescence is recorded), Modulated Population Spectroscopy (MPS, Section 1.2.2.3) an intense, fixed frequency, amplitude modulated PUMP laser is used to modulate the population in the upper and lower levels connected by the laser excited transition the modulation is then detected by a frequency scanned PROBE laser), which is an example of Optical Optical Double Resonance (OODR, Section 1.2.2.3). 

Radford (1961, 1962) and Radford and Broida (1962) presented a complete theory of the Zeeman effect for diatomic molecules that included perturbation effects. This led to a series of detailed investigations of the CN B2E+ (v — 0) A2II (v = 10) perturbation in which many of the techniques of modern high-resolution molecular spectroscopy and analysis were first demonstrated anticrossing spectroscopy (Radford and Broida, 1962, 1963), microwave optical double resonance (Evenson, et at, 1964), excited-state hyperfine structure with perturbations (Radford, 1964), effect of perturbations on radiative lifetimes and on inter-electronic-state collisional energy transfer (Radford and Broida, 1963). A similarly complete treatment of the effect of a magnetic field on the CO a,3E+ A1 perturbation complex is reported by Sykora and Vidal (1998). The AS = 0 selection rule for the Zeeman Hamiltonian leads to important differences between the CN B2E+ A2II and CO a/3E+ A1 perturbation plus Zeeman examples, primarily in the absence in the latter case of interference effects between the Zeeman and intramolecular perturbation terms. 

A perturbation acts as a window through which normally unobservable states may be viewed. Anticrossing, quantum-beat, and MODR spectroscopies are capable of examining the states in the immediate vicinity of the perturbed level. Optical-optical double resonance (OODR) allows systematic exploration of states far above and below the perturbed level. Gottscho, (1979) utilized an... 

Millimeter wave spectroscopy with a free space cell such as a Broida oven is more sensitive than lower frequency microwave spectroscopy. However, the higher J transitions monitored by millimeter wave spectroscopy often do not show the effects of hyperfine structure. In the case of CaOH and SrOH, the proton hyperfine structure was measured in beautiful pump-probe microwave optical double resonance experiments in the Steimle group [24,68], They adapted the classic atomic beam magnetic resonance experiments to work with a pulsed laser vaporization source and replaced the microwave fields in the A and C regions by optical fields (Fig. 15). These sensitive, high-precision measurements yielded a very small value for the proton Fermi contact parameter (bF), consistent with ionic bonding and a... 

Electron-impact Spectra.—A review of electron-scattering spectroscopy has appeared.265 Electron-impact spectra have been reported of helium,263 H and He,267 Li,258 Ba,259 Hg,280 H2,261 CO,282 Rbl and KI,283 NO and N20,284 water,286 ammonia and methane,2866 N02,288 and C02.287 The study on NOa yields the interesting result that the 2B2 state is asymmetric, possessing different equilibrium bond lengths between the N atom and each atom this can explain the results of recent microwave-optical double-resonance experiments.288... 

Double-resonance Spectroscopy.—A review has been given of double-resonance methods in spectroscopy.378 Attention will be focused here on optically (usually phosphorescence) detected magnetic resonance experiments (ODMR). Microwave-optical double-resonance experiments have been carried out on the spectrum of gaseous N02,379 permitting assignment of the rotational = 0—4 side-bands of the 493 nm band. 

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