A measurement of the lambda-type doubling spectrum of the CH radical by microwave-optical double resonance: further characterization of the A2Δ state

1984 ◽  
Vol 62 (12) ◽  
pp. 1563-1578 ◽  
Author(s):  
Christopher R. Brazier ◽  
John M. Brown
Keyword(s):  
Precise Measurement ◽  
Double Resonance ◽  
Laser Induced Fluorescence ◽  
Effective Hamiltonian ◽  
Optical Double Resonance ◽  
Molecular Hamiltonian ◽  
Line Widths ◽  
Ch Radical ◽  
Π State

Several lines in the lambda-doubling spectrum of the CH radical in its ground 2Π state have been recorded by the technique of microwave-optical double resonance. Individual lines in the (0, 0) band of the A2Π–X2Π system at 431 nm were pumped with a dye laser and the absorption of microwave radiation was detected as an increase in the level of fluorescence. The microwave transition frequencies were measured to an accuracy of 0.1 MHz and the results were used to determine values for the lambda-doubling parameters in the molecular effective Hamiltonian. Several lines in the (0, 0) band of the A–X system were also recorded with sub-Doppler line widths using the saturation technique of intermodulated fluorescence. The proton hyperfine structure was easily resolved. The very small effects of lambda-doubling in the A2Δ state were also detected for the higher rotational levels by precise measurement of the laser induced fluorescence spectrum. The values obtained for the parameters that described these effects in the molecular Hamiltonian are discussed.

Optical double resonance with laser-induced fluorescence detection

1982 ◽  
Vol 307 (1500) ◽  
pp. 603-615 ◽  
Keyword(s):  
Free Radicals ◽  
Laser Beam ◽  
Hyperfine Structure ◽  
Fluorescence Detection ◽  
Molecular Species ◽  
Double Resonance ◽  
Laser Induced Fluorescence ◽  
Intense Laser ◽  
Laser Induced Fluorescence Detection ◽  
Optical Double Resonance

The saturation of level populations induced in a molecule by an intense laser beam may be probed by a second beam at the same or a different frequency. A number of schemes have been based on this principle for simplifying complex spectra or for achieving sub-Doppler resolution. Fluorescence detection provides the sensitivity for studies on free radicals and other transient molecular species. The two beams may be provided by two separate lasers, or by sideband modulation of a single laser. These techniques are reviewed. Emphasis is placed on recent studies of hyperfine structure, of Stark splittings, and of Zeeman splittings.

Ionization-detected optical–optical double resonance spectroscopic studies of moderate energy Rydberg states of calcium monofluoride

2001 ◽  
Vol 79 (2-3) ◽  
pp. 247-286 ◽  
Author(s):  
C M Gittins ◽  
N A Harris ◽  
M Hui ◽  
R W Field
Keyword(s):  
Vibrational Excitation ◽  
Principal Quantum Number ◽  
Double Resonance ◽  
Rydberg States ◽  
Quantum Defect ◽  
Resonance Spectroscopy ◽  
Effective Hamiltonian ◽  
Optical Double Resonance ◽  
Hamiltonian Model ◽  
Calcium Monofluoride

This paper describes a systematic investigation of quasi-bound Rydberg states of calcium monofluoride (CaF) existing between the molecule's υ+ = 0 and 1 ionization thresholds. Experiments utilized ionization-detected optical–optical double resonance spectroscopy to assign states as belonging to one of the six core-penetrating ([Formula: see text] [Formula: see text] 2) or to a core-nonpenetrating ([Formula: see text] [Formula: see text] 3) Rydberg series. Most states observed had effective principal quantum number, ν, between 12 and 18 and one quantum of vibrational excitation in the CaF+ ion-core, although lower ν, υ [Formula: see text] = 2 states were also identified. Core-nonpenetrating states were observed both directly and through avoided crossings with core-penetrating states. Five of the seven [Formula: see text] components in the f-complexes derived from Ca+, 13f and n = 14f, have been identified. We present a detailed analysis of the CaF electronic structure for 12.5 [Formula: see text] ν [Formula: see text] 14.6, υ = 1 using an effective Hamiltonian model to describe CaF+ ion-core-induced [Formula: see text]-mixing between [Formula: see text] [Formula: see text] 3 (s,p, d, and f) Ca+ atomic orbitals. An observed avoided crossing between the 14.19 2Σ+, υ = 1 and 14f ([Formula: see text] = –3), υ = 1 states implies that the previously identified 0.19 Σ+ core-penetrating series has 20–30% f 2υ+-character. The effective Hamiltonian approach accounts for much of the data, however, a complete accounting requires the use of multichannel quantum defect theory (MQDT). An MQDT analysis of the data presented here is provided in a companion paper by Jungen and Roche in this issue. The effective Hamiltonian model enabled derivation of electrostatic properties of the CaF+ core as well as the 0.14Δ series quantum defect derivative, [dδ/dR]Re+, which governs the exchange of energy between the Rydberg electron and the CaF+ ion-core. The CaF+ electric quadrupole moment, defined with the coordinate origin at the center-of-charge, is 11.3 ± 0.5 a.u. PACS Nos.: 33.40+f, 33.80Eh, 33.15Ry, 33.15Ta

scholarly journals Precise Measurement of Hyperfine Structure of Cesium 7S1/2 Excited State

2020 ◽  
Vol 10 (2) ◽  
pp. 525 ◽  
Author(s):  
Yunhui He ◽  
Jiabei Fan ◽  
Liping Hao ◽  
Yuechun Jiao ◽  
Jianming Zhao
Keyword(s):  
Excited State ◽  
Hyperfine Structure ◽  
Precise Measurement ◽  
Double Resonance ◽  
Probe Laser ◽  
Transition Line ◽  
Coupling Laser ◽  
Electro Optic ◽  
Fabry Perot ◽  
Optical Double Resonance

We present a precise measurement of the hyperfine structure of cesium 7 S 1 / 2 excited state by employing electromagnetically induced spectroscopy (EIS) with a cesium three-level cascade ( 6 S 1 / 2 − 6 P 3 / 2 − 7 S 1 / 2 ) atom in a room temperature vapor cell. A probe laser, λ p = 852 nm, was coupled to a transition | 6 S 1 / 2 ⟩ → | 6 P 3 / 2 ⟩ , related frequency locked to the resonance hyperfine transition of | 6 S 1 / 2 ⟩ → | 6 P 3 / 2 ⟩ with a Fabry–Perot (FP) cavity and an electro-optic modulator (EOM). A coupling laser, λ c = 1470 nm, drove the | 6 P 3 / 2 ⟩ → | 7 S 1 / 2 ⟩ transition with the frequency scanned over the | 6 P 3 / 2 ⟩ → | 7 S 1 / 2 ⟩ transition line. The hyperfine level interval was extracted to be 2183.61 ± 0.50 MHz by analyzing EIS spectroscopy. The optical–optical double-resonance (OODR) spectroscopy is also presented for comparison, with the corresponding value of the hyperfine level interval being 2183.48 MHz ± 0.04 MHz, and the measured hyperfine splitting of excited 7 S 1 / 2 state is shown to be in excellent agreement with the previous work.

"Spectrum-only" assignment of core-penetrating and core-nonpenetrating Rydberg states of calcium monofluoride

2004 ◽  
Vol 82 (6) ◽  
pp. 791-803 ◽  
Author(s):  
Jeffrey J Kay ◽  
Daniel S Byun ◽  
Jason O Clevenger ◽  
Xing Jiang ◽  
Vladimir S Petrović ◽  
...  
Keyword(s):  
Double Resonance ◽  
Rydberg States ◽  
Electric Quadrupole ◽  
Resonance Spectroscopy ◽  
Effective Hamiltonian ◽  
Rydberg Series ◽  
Optical Double Resonance ◽  
Hamiltonian Model ◽  
Calcium Monofluoride ◽  
Double Resonance Spectroscopy

Rydberg states of calcium monofluoride in the n* = 17–20 region have been observed by ionization-detected optical–optical double-resonance spectroscopy via the D2Σ+ v = 1 intermediate state. All members of the six core-penetrating Rydberg series in the n* = 17–20 region and several components of the 17f and 17g core-nonpenetrating Rydberg states have been assigned. While the assignment of core-penetrating Rydberg states is straightforward without use of an effective Hamiltonian model, "spectrum-only" assignment of core-nonpenetrating states is complicated because strong l-uncoupling causes the core-nonpenetrating states to evolve rapidly from Hund's case (b) to Hund's case (d) coupling. We describe "spectrum-only" assignment procedures, developed in the spirit of Gerhard Herzberg, that can be used to assign optical–optical double-resonance spectra of core-penetrating and core-nonpenetrating Rydberg states using only information contained in the spectrum rather than predictions derived from an effective Hamiltonian model. The ambiguities that arise in the assignment of each class of states are discussed in detail.Key words: CaF, electric quadrupole moment, Rydberg states, laser spectroscopy.

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