Influence of parameters of gas medium on the fluorescence of iodine molecules 129I2, 127I129I and 127I2 excited by semiconductor laser radiation

Calculated and experimental results of studies of the influence of vapor temperature of iodine molecules (¹²⁹I₂, ¹²⁷I¹²⁹I, and ¹²⁷I₂) and pressure of the analyzed medium on the intensity of fluorescence of the molecules excited by semiconductor laser radiation in the red spectrum region are reported. It is demonstrated that depending on the wavelength of laser radiation there exist different ranges of temperatures and pressure values at which the fluorescence intensities of each of the indicated iodine molecules reach their maximum values.     

Hyperfine structure of 127I2 and 129I2 optical absorption lines

The hyperfine structure of ¹²⁷I₂ and ¹²⁹I₂ rovibronic absorption lines was investigated using either laser induced fluorescence of a collimated molecular beam or saturated absorption in a cell. From the measurements a value for the quadrupole moment ratio ${}^{129}\text{Q}{}^{127}\text{Q}\text{=}\text{0.699}$ is deduced, in good agreement with the result obtained from pure quadrupole spectra in the rf range.     

Theoretical assignment of the observed hyperfine structure in the saturated absorption spectra of I2129 and I127I129 vapors in the 633 nm wavelength region

The detailed structure observed in the saturated absorption spectrum of I₂¹²⁹ vapor in the 633 nm wavelength region in the spectral interval reported by Knox and Pao, has been interpreted to be the overlap between the hyperfine lines of the 8-4 P(54) line of I₂¹²⁹ and the 6-3 P(33) line of the I¹²⁷I¹²⁹ vapor. In this assignment, the nuclear electric quadrupole and nuclear magnetic terms in the Hamiltonian were diagonalized exactly and certain molecular parameters were varied to obtain the best fit with the observed spectrum. For I₂¹²⁹, the calculated distance (separation) of the center of the 8-4 P(54) line from the line center of the Ne²⁰ 633 nm laser transition is 0.04 cm^?1 and the RMS deviation between the theoretical and experimental hyperfine spectra is 0.3 MHz. Although the calculated frequency of R(60) transition in the 8-4 band is only 0.03 cm^?1 from the center of the laser line, we conclude on the basis of the larger RMS error (0.5 MHz) that this latter transition is less likely to be that responsible for the structure discussed in this paper.     

Hyperfine spectra in iodine-129 at 612 nm

The complete hyperfine spectrum of a transition in ¹²⁹I₂ at a wavelength of 612 nm that overlaps the spectrum of ¹²⁷I₂ reported by Bennett and Cerez has been obtained, together with parts of the spectra of other transitions in ¹²⁹I₂ and ¹²⁷I₂. The lasers used for this work are described and the frequencies for the various hyperfine components are outlined.     

Identification of hyperfine structure components of the iodine molecule at 640 nm wavelength

The frequencies and the relative intensities of rotation-vibration transitions of ¹²⁷I₂, ¹²⁹I₂ and ¹²⁷I¹²⁹I near the HeNe laser emission wavelength of 640 nm have been calculated. Interpolation formulas for the differences of the electric quadrupole constants ΔeQq and of the spin-rotation constants ΔC of ¹²⁷I₂ are given. Most of the weak saturated-aborption lines, elsewhere published, have been identified as cross-over and forbidden lines of the transitions P(10)8-5 and R(16)8-5.     

Possibility of separating the isotopes127I and129I with the aid of a photodissociation iodine laser

A method for separating iodine isotopes is proposed, based on the large difference between the rate constants of the excited I*(²P_1/2) and unaxclted iodine atoms with radicals CF₃ and with Cl₂ molecules, and on the possibility of selectively acting on the₁₂₇I atoms in the states²P_1/2 and²P_3/2 by radiation from a photodissociation R¹²⁷I iodine laser (λ = 1.315 μm). The possibility of separating the pure isotope¹²⁹I and the mixture¹²⁷I with¹²⁹I is investigated.     

Wavelength stabilization of an Ar+ laser with an external129I2 absorption cell

Wavelength stabilization of the green Ar⁺ laser line at 514.5 nm by¹²⁹I₂ absorption was found to be more favourable than by¹²⁷I₂ absorption because the maximum of¹²⁹I₂ absorption is closer to the center of the 514.5 nm gain curve. A simple method for stabilizing a short air cooled laser with only one servo loop is given, yielding a stability of 10⁻⁸ λ.     

Mössbauer spectroscopy of laser annealed tellurium implanted silicon (II).129I

Laser annealed^129mTc-implanted silicon has been investigated using¹²⁹I Mössbauer spectroscopy. At least three dopedependent charge states of substitutional iodine are found. For heavily doped p-type Si a single line component S₁, with isomer shift S=0.96(4) mm/s w. r. t. Cu¹²⁹I and an effective Debye temperature ?′=196(3) K is observed. This component is attributed to I⁺⁺. For compensated Si a single line component, S₂, assigned to I⁺, with S=2.39 (4) mm/s and ?′=170 (3) K is found. For n-type Si, a component S₃, characterized at 4.2 K by S=2.15 (4) mm/s and a quadrupole splitting eQV_zz/h=452 (8) MHz (n?0)is observed. At higher temperatures S₃ shows quadrupole relaxation and its recoilless fraction becomes strongly anisotropic. This behaviour is explained on the basis of a transition from a static to a dynamic Jahn-Teller distortion. Component S₃ has been attributed to I⁰. In the spectra of compensated and n-type Si a less well-defined component Q, with parameters resembling those of S₃ but showing no quadrupole relaxation, is observed. This component has tentatively also been assigned to I^o. The results can be understood qualitatively on the basis of a simple MO-model.     

Structural phase transitions in the Cs3Sb2I9 crystal

A sequence of two phase transitions at 85.3±0.6 K and 72.6±0.4 K is observed in hexagonal Cs₃Sb₂I₉. The NQR spectra of ¹²⁷I are analyzed, optical polarization studies are made, and the thermal properties, linear expansion coefficients, and stiffness constants are measured over a broad range of temperatures below room temperature. Fiz. Tverd. Tela (St. Petersburg) 39, 946–948 (May 1997)     

Laser-induced-fluorescence Fourier transform spectrometry of the XOg+ state of I2: Extensive analysis of the BOu+ → XOg+ fluorescence spectrum of 127I129I and 129I2

An extensive rotational analysis of the vibrational levels of the XO_g⁺ state of ¹²⁷I¹²⁹I (5 ≤ v″ ≤ 110) and ¹²⁹I₂ (4 ≤ v″ ≤ 108) has been done from laser-induced-fluorescence analyzed with a Fourier transform spectrometer. The usual Dunham relationships are checked. For the range explored the lines can be recalculated with an accuracy better than 0.010 cm⁻¹ and even 0.005 cm⁻¹ for low J values. Checks are done from absolute hyperfine measurements.     

He(I) photoelectron spectroscopy of anions in adiponitrile solution

He(I) photoelectron spectra are reported of solutions of salts in adiponitrile in which peaks characteristic of the anions are visible; the vertical ionisation energies of these peaks are 6.91 and 7.85 (I^?), 7.6 (Br^?), 8.1 (Cl^?), 7.0 (CNS^?), 8.1 and 6.8 (NO₂^?), and 7.6eV (SO₄^2?). The salts examined were tetra-n-butyl ammonium (NO₂^?, I^?, Br^?, Cl^?, CNS^?, SO₄^2?), N-methylpyridinium I^?, trimethylphenylammonium I^?, choline I^?, methyltrioctylammonium I^? and methyltriphenylphosphonium Br^?. The relationship between these spectra and the charge transfer to solvent spectra of the anions is discussed.     

Collective quadrupole dynamics and the band structure of the nucleus 127Cs

Excited states of ¹²⁷₅₅Cs were populated in the ¹²⁷I(α, 4n)¹²⁷Cs reaction. Singles, prompt and delayed γ-ray spectra, γγ coincidence spectra, angular distributions and excitation functions were measured, and negative and positive parity bands established. The h_{$\text{11}\text{2}$} families of excited levels in ^{127, 129}Cs and ¹³³La were reproduced by core-particle coupling calculations, regardless of whether the cores were taken to be rigid triaxial rotors or to have all five quadrupole degrees of freedom. The hamiltonians for the latter case were based on microscopic calculations which attribute an important role to the γ-dependence of the mass functions for collective quadrupole motion. From a core-quasiparticle analysis of the positive-parity levels in ¹²⁷Cs, indications of a “Coriolis attenuation” anomaly were inferred.     

Single-mode operation of an Ar+ laser with an intracavity I2 absorption cell

A multi-mode argon ion laser was furnished with an intracavity¹²⁷I₂ absorption cell for the purpose of mode suppression at the wavelength of 514.5 nm. Singlemode operation was achieved with an 8 cm long cell having a¹²⁷I₂ vapour pressure of 0.27 mbar (0.2 Torr).     

CH3I: Isotope shift for 129I in the v6 band

The isotope shift in the v₆ band of CH₃I has been measured with high resolution for the radioisotope ¹²⁹I (half-life = 1.6 × 10⁷ y) with respect to the stable ¹²⁷I, using tunable diode laser spectroscopy. The average shift obtained from 30 transitions, free from interference in the ^RQ(J, 3) and ^RQ(J, 4) branches, amounted to (-0.0135 ± 0.0006) cm^-1. The abundance ratio ¹²⁹I/¹²⁷I in the gas mixture was determined spectroscopically on ^RQ(16, 3) and found to be (0.032 ± 0.003), as compared to a mass-spectrometric analysis of (0.030 ± 0.001). The self and air broadening coefficients measured on ^RR(6, 0) of CH₃¹²⁷I were (32 ± 3) MHz Torr^-1 and (10.4 ± 1.5) MHz Torr^-1 respectively. The line strengths for ^RQ(16, 3) were found to be (2.0 ± 0.2) × 10^-21 cm^-1 mol^-1 cm² for both CH₃¹²⁷I and CH₃¹²⁹I.     

Double photoionisation spectra of HI,CH3I and CF3I from TOF-PEPECO measurements

Double photoionisation spectra of HI, CH₃I and CF₃I have been measured by the TOF-PEPECO technique, providing complete information on electron energy distributions. The lowest energy states of HI²⁺ and CH₃I²⁺ are identified and their vibrations are resolved. Possible reasons for the markedly different CF₃I spectrum are discussed. There is evidence for atomic autoionisation of iodine as a pathway contributing to the double photoionisation.     

Local environment of Te in GaTe and Ga2Te3 studied with119Sn and129I Mössbauer spectroscopy

The compounds GaTe and Ga₂Te₃ have been studied with Mössbauer source spectroscopy, using the decays^119mTe→¹¹⁹Sb→¹¹⁹Sn and^129mTe→¹²⁹I. For Ga₂Te₃, which has a defect zincblende structure, the spectra give satisfactory fits using two components with intensity ratio roughly 2∶1, in agreement with the two crystallographic sites in this compound. The Mössbauer spectra of GaTe are not easily understood in terms of the three inequivalent Te sites present in this compound. The relevance of these results for the interpretation of Mössbauer spectra observed after high-dose Te implantation in GaAs is discussed.     

Lattice displacement waves in AuTe2

¹²⁵Te and¹²⁹I Mössbauer spectra were studied of AuTe₂, AuAgTe₄, and AuCuTe₄. A distribution in hyperfine parameters is needed to obtain a satisfactory fit of the¹²⁹I spectra, and is interpreted in favor of lattice displacement waves recently observed in these compounds.     

Nuclear magnetic resonance on oriented 11/2− 129mXe and131mXe in Fe

The magnetic hyperfine splitting frequenciesν _M=¦gμ _NB_HF/h.¦ of the 11/2^? isomeric states^129m Xe (T_1/2=8.9d) and^131mXe (T_1/2=11.8d) in Fe were measured with nuclear magnetic resonance on oriented nuclei at temperatures of 10–15 mK as 188.0(1) MHz and 209.8(1) MHz, respectively, the samples being prepared with the technique of recoil implantation after (α, x n) reactions. The magnetic moments of^129m Xe and^131m Xe are deduced to be (?)0.8914(6)μ _N and (?)0.9943(6)μ _N, respectively. The missing γ-anisotropies for allγ-transitions following the decay of 36.4d ¹²⁷Xe indicateI=1/2 for the ground state spin of¹²⁷Xe.     

Dissociative multiple photoionization of Br2, IBr,and I2 in the VUV and X-ray regions: a comparative study of the inner-shell processes involving Br(3d,3p,3s) and I(4d,4p,4s,3d,3p)

Dissociative multiple photoionization of the bromine, the iodine monobromide, and the iodine molecules in the Br(3d,3p,3s) and I(4d,4p,4s,3d,3p) inner-shell regions has been studied by using time-of-flight (TOF) mass spectrometry coupled to synchrotron radiation in the ranges of 90∼978 eV for Br₂, 60∼133 eV for IBr, and 86∼998 eV for I₂. Total photoion and photoion–photoion coincidence (PIPICO) yields have been recorded as functions of the photon energy. Here, giant shape resonances have been observed beyond the thresholds of the inner-shells owing to the Br(3d¹⁰)→Br(3d⁹ϵf), I(4d¹⁰)→I(4d⁹ϵf), and I(3d¹⁰)→I(3d⁹ϵf) transitions. The dissociation processes of the multiply charged parent ions have also been evaluated from variations of photoelectron–photoion coincidence (PEPICO) and PIPICO spectra with the photon energy. From each Br(3p_3/2) (189.9 eV) and I(4p_3/2) threshold (129.9 eV), quintuple ionization of the molecules begins to play important roles in the photoionization, subsequently yielding ion pairs of X³⁺–X²⁺ (X=Br, I). From the I(3d_5/2) threshold (627.3 eV), loss of six electrons from iodine molecule additionally begins to play a minor role in the multiple photoionization, giving rise to the formation of ion pairs of either I³⁺–I³⁺ or I⁴⁺–I²⁺. A direct comparison of the strengths and the ranges of the I(4d) and Br(3d) giant resonances was successfully made from dissociative photoionization of IBr. Over the entire energy range examined, 60<E<133 eV, biased charge spread relevant to the specific core-hole states of IBr is observed, presumably reflecting the fact that charge localizes mostly in the excited atoms, which can be accounted for mainly by a two step decay via a fast dissociation followed by autoionization upon the VUV absorption.     

Interferometric frequency measurements of 130Te2 transitions at 486 nm

Doppler-free spectra of ¹³⁰Te₂ have been investigated in the region of 486 nm, close to the Balmer-β transitions atomic hydrogen and deuterium. The frequency ratios between a 633 nm He-Ne laser stabilized to the 11-5 R(127) “i” transition in ¹²⁷I₂ and two of these ¹³⁰Te₂ Doppler-free components have been measured interferometrically to a precision of 2 parts in 10¹⁰ (one standard deviation). These measured components constitute useful transfer standards for the measurement of absolute frequencies of both the Balmer-β transitions and the 243-nm two-photon 1S-2S transitions in hydrogen and deuterium.