C.W. Optical–Optical Double Resonance in /2: Hyperfine Structure in the E 0−g+– B 0u+ System

International audienceHyperfine structure for several E(0g+)–B(0u+) rovibrational transitions has been measured for the first time. Two single frequency lasers were used to excite E(0g+)(υ*, J*)–B(0u+)(υ′, J′) – X(1Σg+)(υʺ, Jʺ) transitions which result in Doppler-free E(0g+)(υ*, J*)–B(0u+)(υ′, J′) fluorescence excitation spectra. Hyperfine parameters are obtained for E(0g+)υ = 11 (eQq = +483±4 MHz, C = –210±3 kHz) and E(0g+)υ = 8 (eQq = +492.3±2.5 MHz, C = –205±3 kHz). The non-zero C constant is shown to arise from mixing with a nearby 1g state and the eQq constant shows the 3P2(I+) origin of the E(0g+) state

Calculation of the magnetic hyperfine interaction in the E and X states of iodine with the separated-atom theory

International audienceUsing the separated-atom representation of a molecular state, simple analytic calculations of the magnetic hyperfine interaction in the E and X states of I2 are given. The value of the magnetic hyperfine constant C in the ion-pair state E was found to be strongly dependent on the assumed dissociation asymptote for this state. Comparison with the experimental result clearly shows the correlation of the E state to the 3P2 state of I+. In the ground state X our predicted value for the C constant in the v″=83 level, C83=51 kHz is in good agreement with the measured value C83=59±5 kHz. Thus, the separated-atom theory provides a simple way of evaluating the hyperfine structure of molecular states with respect to their dissociation limits, giving an excellent test of their atomic origin

Hyperfine Predissociation in Br2

International audienceHyperfine structure of several rovibronic transitions in the B-X system of 79Br2 has beenanalyzed and the quadrupolar and nuclear spin rotation hyperfine coupling constants havebeen obtained. A strong hyperfine predissociation effect has been observed for the first timein Br2 and the related hyperfine and rotational parameters were determined in the B(0+) v’11 level

HYPERFINE PREDISSOCIATION IN BR2

International audienceThe only known example of hyperfine predissociation occurs in the I2 molecule. It has been extensively studied (1). Observation of a similar effect in Br2 is hindered by a strong rotational predissociation (αJ(J+1)) but the longer radiative lifetime of B3Π+Ou state of Br2 favors its detection at low J (1). With a supersonic Br2 beam the populations of low J values is enhanced. The excitation spectrum is obtained at ∼ 1 MHz resolution. The hyperfine structure of various lines display strong intensity anomalies. From the relations given in (1) we were able to determine the radiative lifetime and rotational and hyperfine predissociation parameters for some levels of the B3Π+Ou state of Br

EMISSION SPECTRA FROM THE CHEMICAL REACTION OF HEATED Cu WITH METASTABLE OXYGEN AND Cl2, COMPARISON WITH LASER INDUCED FLUORESCENCE AND ABSORPTION SPECTRA OF CuCl2

We present the results of a spectroscopic investigation of CuCl2 vapour obtained from laser induced fluorescence recorded by Fourier transform spectrometry, and give preliminary spectroscopic constants for the [MATH] and [MATH] states of Cu35Cl2. Coupled with data obtained from absorption experiments on CuCl2, this work brings us closer to understanding the mechanism of the reaction of copper with chlorine in the presence of singlet oxygen ([MATH]), which is accompanied by an intense red flame. This emission has been proposed as a possible candidate for the production of a visible or infrared chemical laser. We consider this question in view of lifetime measurements on the [MATH] state of the CuCl2 molecule, now accepted to be the emitting species, and also compare the infrared and visible spectra of CuCl2 with the chemiluminescence recorded around 1.2 and 0.7 µm