A. De Lorenzi

Sequential ion implantation of copper and cobalt in silica glass: A study by synchrotron radiation techniques

Abstract Copper–cobalt nanostructures are expected to exhibit peculiar magnetic and optical properties that make them interesting for several application fields. In particular, nanoclusters of these metals can be formed upon ion implantation in dielectric matrices. In this work, Co + and Cu + ions were sequentially implanted into fused silica. Samples were analyzed by different synchrotron radiation-based techniques, namely, extended X-ray absorption fine structure spectroscopy and grazing incidence X-ray diffraction. The obtained cluster structure, and so its magnetic features, are observed to depend on the sequential implantation order.

High resolution FTIR spectrum of vinyl fluoride near 9 μm: rovibrational analysis of the v 7 band

The Fourier transform infrared spectrum of CH2=CHF has been investigated in the v 7 band region around 115 5 cm-1 at a resolution of about 0·002 cm-1. This fundamental of symmetry species A′ yields an a/b hybrid band with a prevalent contribution of the a-type component. The band is affected by first-order b-Coriolis resonance with the v 9 + v 12 combination, and the interactions are markedly stronger for the K′ a = 11 and 12 levels; local perturbations with crossings due to higher-order a- and b-Coriolis resonances have also been observed. The rovibrational analysis led to the identification of more than 2900 lines of v 7 with J ⩽ 6>4 and K a ⩽ 1>8, while no features were detected for the v 9 + v 12 band. Using Watsons A-reduction Hamiltonian in the I r representation, the present ground state combination differences combined with available microwave data led to improved sextic distortion terms for the ground state. Of the assigned lines, 2329 free of major resonance contribution provided excited state ...

Infrared study of the ν5 fundamental of CF2HCl by FTIR spectroscopy

Abstract The infrared spectrum of natural CF 2 HCl has been investigated in the ν 5 region at a resolution of ca. 0.004 cm −1 using a Fourier transform infrared spectrometer. The ν 5 fundamental, which can be approximately described as a CF 2 deformation mode, gives rise to an a c hybrid band. The rovibrational analysis has been carried out in the P and R branches, and more than 1000 lines belonging to CF 2 H 35 Cl have been assigned. Transitions with K ′ a ≤ 6, J ′ up to 48 ( a -type) and K ′ e ≤ 11, J ′ up to 33 ( c -type) have been identified in the region investigated. From the assigned transitions a set of spectroscopic constants using Watsons A -reduction Hamiltonian has been derived for CF 2 H 35 Cl ν 5 band. Simulations in the Q -branch region enabled us to establish the character of the hybrid band which was determined to be composed of about 30% of a and 70% of c components.

Infrared study of the ν1 band of CF2Cl2 by diode laser spectroscopy

Abstract The infrared spectrum of natural CF2Cl2 has been investigated in the ν1 band region at a resolution of ∼0.002 cm−1 using a tunable diode laser spectrometer. The measurements have been carried out at low temperature (∼200 K) in order to deplete the “hot band” contributions; nevertheless, the spectra still exhibit an extremely high density of lines due to the presence of different chlorine isotopic features. Many P- and R-branch transitions of the CF235Cl2ν1 band covering J and Ka values up to 45 and 9, respectively, have been identified. The band was found to be perturbed by Coriolis-type resonance and at least two nearby states, ν8 and ν2 + ν7, seem to be involved in the interaction. From the assigned transitions a set of effective constants for the ν1 fundamental of CF235Cl2 has been derived.

High-resolution FTIR spectroscopy of the C—Cl stretching mode of vinyl chloride

The vibration—rotation spectra of natural CH2=CHCl and mono-isotopic CH2=CH37Cl (isotopic purity, 95%) have been studied in the ν8 band region near 720 cm−1 with a resolution of 0.005 cm−1, by using a Fourier transform infrared spectrometer. This vibration of symmetry species A′ is expected to give rise to an a/b hybrid band with a predominant contribution of the a-type component. Both J and K structures have been resolved in different subbranches and the rovibrational analysis led to the assignment of about 3300 (J  78, K a  16) and more than 3000 (J  79, K a  16) transitions of 35Cl and 37Cl isotopomers, respectively. The P- and R-branch spectrum with high J values shows a series of lines arising from oblate-type near-degeneracy. Using Watsons A-reduction Hamiltonian in the Ir representation, a least-squares fit of the identified transitions provided excited state constants of the ν8 band for both the isotopic species, which turned out to be free from perturbations.

Infrared laser spectroscopy of the nu band of CH2--CH37Cl

The infrared spectrum of CH2=CH37Cl has been investigated in the υ5 band region around 1370 cm-1, at Doppler-limited resolution, using a tunable diode laser spectrometer. This vibration of symmetry species A′ yields an a/b hybrid band exhibiting patterns characteristic of molecules approaching the prolate symmetric top limit. The J fine structure was resolved in most of the (P,R)QK clusters and the rovibrational analysis in the P, Q and R branches led to the assignment of about 800 transitions with J ⩽ 49 and Ka ⩽ 11. The band is affected by different Coriolis-type resonances with the nearby states υ8 + υ12 and υ9 + υ10. Using the Watsons A-reduction Hamiltonian in the Ir representation, a least-squares fit of about 650 transitions free of major resonance contribution provided a set of effective molecular constants for the v 5 = 1 state of CH2=CH37Cl. From spectral simulation the |Δµ a /Δµ b | dipole moment ratio was estimated to be 0·74 ± 0·08.

Infrared spectrum and rovibrational analysis of the ν6 band of vinyl chloride by diode laser spectroscopy

Abstract The gas-phase infrared spectrum of natural CH 2 CHCl has been measured in the ν 6 band region near 1281 cm −1 at a resolution of about 0.002 cm −1 using a tunable diode laser spectrometer. This vibration of symmetry species A ′ is expected to give rise to an a b hybrid band, which resulted mainly composed by a -type transitions. The spectrum investigated exhibits patterns characteristic of molecules approaching to the prolate symmetric-top limit; the rovibrational analysis in the P , Q , and R branches led to the assignment of more than 1000 lines with J ≤ 40 and K a ≤ 14. The band was found to be affected by Coriolis-type resonance and the ν 9 + ν 11 state seems to be involved in the perturbation. From a simultaneous fit of the obtained ground state combination differences, together with microwave data available in the literature, a set of ground state constants up to the quartic coefficients has been determined using the Watsons A -reduction Hamiltonian in the I ′ representation. A least-squares fit of the assigned transitions yielded a set of effective constants for the first excited vibrational state of the ν 6 of CH 2 CH 35 Cl.

High-resolution FTIR spectrum of the ν5 band of 1,1-difluoroethylene around 550 cm−1

Abstract The infrared spectrum of CF 2 CH 2 recorded in the range 400–4000 cm −1 with a Fourier transform infrared spectrometer has been studied in the ν 5 region. This fundamental approximately described as a CF 2 scissor mode gives rise to an a -type band showing in most regions of the spectrum distinct patterns characteristic of molecules approaching the oblate symmetric top limit. The rovibrational analysis extended to the P , Q , and R branches led to the identification of about 3000 transitions covering J and K a values up to 70 and 46, respectively. Using Watsons A -reduction Hamiltonian the assigned transitions provided a set of accurate rotational and centrifugal distortion constants for the first excited vibrational state of the ν 5 band of CF 2 CH 2 .

A Fourier transform infrared study of CH2=CHF in the v 4 band region near 1650 cm-1

The vibration-rotation spectrum of vinyl fluoride has been investigated in the v 4 band region around 1656 cm-1 at a resolution of about 0·003 cm-1 using a Fourier transform infrared spectrometer. This fundamental of symmetry species A′ is mainly affected by first-order b-Coriolis resonance with the close-lying v 8 + v 12 and 2v 9 + v 12 levels. The rovibrational analysis led to the identification of about 2000 lines with J ˇ- 58 and K a ˇ- 16 of the predominant a-type component. Using Watsons A-reduction Hamiltonian in the I r representation, a set of effective constants for the v 4 band was obtained employing transitions free of major resonance contribution. Even though no direct transitions to the perturbing levels have been observed, the determination of a few constants for the perturber v 8 + v 12 has been achieved.

High-resolution FTIR study of the ν11 and 2ν11 bands of CF2CH2

Abstract The Fourier transform infrared spectrum of CF 2 CH 2 recorded in the range 400–4000 cm −1 has been analyzed in the ν 11 and 2 ν 11 regions around 802 and 1611 cm −1 , respectively, at a resolution of about 0.0017 cm −1 . The fundamental ν 11 , approximately corresponding to the CH 2 wagging mode, gives rise to a c -type band whose rovibrational analysis in the P and R branches led to the assignment of more than 5200 transitions with J ≤ 70 and K a ≤ 63. For the 2 ν 11 overtone ( a -type band) the investigation could also be extended to the Q branch, and more than 3300 transitions with J ≤ 58 and K a ≤ 27 have been identified. From a simultaneous analysis of ground state combination differences due to the ν 11 and the recently studied ν 5 bands, together with available literature data mostly consisting of microwave measurements, a set of ground state parameters up to all the sextic centrifugal distortion constants has been obtained. Using the Watsons A -reduction Hamiltonian in the I r representation, least-squares fits of the assigned transitions provided reliable sets of molecular constants for both the first and second excited vibrational states of ν 11 of CF 2 CH 2 .