UV Light Irradiation Effects in P-Doped Diamonds: Total Content Determination of Phosphorus Donors.

Upon the UV light irradiation of single-crystal diamonds doped with phosphorus, several effects have been observed. The integral intensity of phosphorus lines in FTIR absorption spectra under UV radiation was increased. A saturation effect depending on the power of the laser radiation was demonstrated. Narrowing of the phosphorus lines, as well as the redistribution of the intensities in their doublets caused by the Jahn-Teller distortion of the donor ground state, was observed. It was found that these effects are associated with the decompensation of the phosphorus donors. An easy, fast, sensitive, and nondestructive, fully optical method for the determination of the total phosphorus donor's concentration in semiconducting diamonds, as well as its compensation ratio, was proposed.

Overtone spectroscopy of v(C=O) stretching vibration of hexafluoroacetone: Experimental and ab initio determination of peak positions, absolute intensities, and band shapes.

Infrared overtone spectra of the ν(C = O) stretching vibration (ν1) of gaseous hexafluoroacetone ((CF3)2C = O, HFA) were recorded in the spectral range of 7450-3300 cm-1 with a resolution of 0.1 cm-1. Experimental absolute IR intensities and vibrational band centers of the overtones 2ν1, 3ν1, 4ν1 of HFA were measured and compared with their ab initio counterparts, calculated by the second-order canonical vibrational perturbation theory (CVPT2). A hybrid potential energy surface (PES) was evaluated using the quantum-mechanical models MP2/cc-pVQZ for harmonic and MP2/cc-pVTZ for anharmonic parts. Cubic surfaces of dipole moment components were determined using the MP2/cc-pVTZ model. The predicted IR intensities for the first and second overtones reproduced the experimental values with a discrepancy of 6% and 9%, respectively. A weak Fermi resonance between the first overtone 2ν1 and combination tone ν1 + ν2 + ν8 was predicted. The appropriate model was employed for simulating the bands studied using: (i) the asymmetric-top vibration-rotational structure of the ν1 mode, (ii) the inhomogeneous band structure due to contributions of the vibrational states populated at the room temperature, and (iii) the homogeneous broadening of each vibration-rotation transition due to the intramolecular vibrational redistribution (IVR). The rotational and vibrational anharmonic constants were taken from the ab initio calculations, whereas the IVR data were obtained from the experimental data of Chekalin et al. (JPCA 2014, 118:955) with a time resolution of ≈100 fs. A good level of agreement of the predicted shapes of bands studied with experiment is achieved.

Data on vibrational spectra of the langasites Ln3CrGe3Be2O14 (Ln = La, Pr, Nd) and ab initio calculations.

In "Lattice dynamics and structure of the new langasites Ln3CrGe3Be2O14 (Ln = La, Pr, Nd): vibrational spectra and ab initio calculations" [1], experimental and calculated results on lattice dynamics of the recently discovered new compounds La3CrGe3Be2O14, Pr3CrGe3Be2O14, and Nd3CrGe3Be2O14 are reported. These compounds belong to the langasite series and constitute a new class of low-dimensional antiferromagnets. The data presented in this article includes IR diffuse transmission spectra of powder samples of Ln3CrGe3Be2O14 (Ln = La, Pr, Nd) registered at room temperature with a Bruker 125HR Fourier spectrometer, Raman spectra taken in the backscattering geometry (also at room temperature) with a triple monochromator using the line 514, 5 nm of an argon laser as an excitation, results of the DFT calculations with the B3LYP and PBE0 hybrid functionals on the optimized crystal structures, eigenfrequencies and eigenvectors of the normal vibrational modes. These data can be used to analyse electron-phonon interaction and multiferroic properties of the new langasites and to compare the lattice dynamics of different langasites. The dataset is available on mendeley data public repository at https://doi.org/10.17632/32grbb4p82.1.