Wide angle X-ray diffraction patterns and 2D-correlation spectroscopy of crystallization in proton irradiated poly(ether ether ketone).

Proton irradiated poly (ether ether ketone) (PEEK) films were crystallized to different extents, and subsequently characterized by wide angle X-ray diffraction technique. The data were analyzed by two-dimensional correlation mapping (2D-CM), in particular: Generalized, hybrid and multiple perturbations correlation approaches. Two asynchronous correlation peaks at (19.1, 18.7) o and at (22.5, 19.1) o were utilized as a measure the crystal perfection and the preferred process; orientation/crystal growth respectively. Proton irradiation not only favored the formation of crystal form II, but also changed the type of orientation within the irradiated films. Differential scanning calorimetry and Raman spectroscopic analysis confirmed the contribution of the previous two factors. Raman spectra indicated that the intensity of both bands at 1595 and 1608 cm-1 decreased on samples crystallized from the melt, but increased on cold crystallized samples. 2D-CM combined with other suitable techniques is a promising in evaluating the structure of polymers and revealing the effect of proton irradiation.

Structure and vibrational properties of oxohalides of vanadium.

We study the structure and vibrational modes of a wide range of oxohalides of vanadium (VOX(n)Y(m); X, Y = F, Cl, Br, I; n, m = 0-3, n + m < or = 3). The results agree well with experimental results for VOCl(3) and VOF(3) and suggest reassignment of the experimentally observed VOF to VOF(2). We provide new assignments for various experimental modes, identifying several intermediates (VOBr(2), VOBr) and mixed structures (e.g., VOCl(2)Br), and discuss formation trends and stabilities.

Gas phase infrared spectrum and ab initio calculations of phosphorus(III) thiocyanide, SPCN.

An attempt has been made to record the gas phase infrared spectrum of phosphorus(III) thiocyanide, SPCN, for the first time. The molecule was generated by an on-line process using phosphorus(III) thiochloride, SPCl, as a precursor passed over heated silver cyanide at about 350 degrees C. The products were characterized by the infrared spectra of their vapors. The low resolution gas phase Fourier transform infrared spectrum shows three of six characterized fundamental modes of SPCN within the range of the spectrometer used at 2151, 743 and 622 cm(-1) These three bands were assigned to nu(1)(C[triple bond]N stretch), nu(2)(S=P stretch), and nu(3)(C--P stretch), respectively. Ab initio self-consistent-field (SCF) molecular orbital (MO) and Møller-Plesset second-order perturbation theory (MP2) calculations were performed to determine the geometry, total energy and the vibrational frequencies of SPCN.

Gas-phase on-line generation and infrared spectroscopic investigations of polyphosphazenes, (NPX2)3 where X=F, Cl and Br.

Gas-phase infrared spectra of polyphosphazenes (phosphonitrilic halides trimer), (NPX2)3 where X=F, Cl and Br have been recorded. The molecules were generated for the first time by an on-line process using solid (NPCl2)3 as a precursor passed over heated sodium fluoride and potassium bromide at about 550 and 700 degrees C for (NPF2)3 and (NPBr2)3 production, respectively. The products were characterized by the infrared spectra of their vapors. The low-resolution gas-phase Fourier transform infrared spectra reported for the first time show strong bands centered at 1295, 1215 and 1200 cm-1, assigned to nu7(E'), in plane PN stretching mode of (NPX2)3, where X=F, Cl and Br, respectively.

The gas-phase on-line production of phosphorus thiotrihalides, SPX3 and their identification by infrared spectroscopy.

A new route has been devised, leading to the production of phosphorus thiotrihalides, SPX3 where X = F, Br and I by an on-line process using phosphorus thiotrichloride, SPCl3 as starting compound gassed over the following heated salts NaF, KBr and KI at 530, 800 and 440 degrees C, respectively. The products have been characterized by their IR spectra, showing bands with PQR type structure, centered at 985, 762, 744 and 715 cm(-1). These bands are assigned to v1(a1), the S=P stretching fundamental modes of SPF3, SPCl3, SPBr3 and SPI3, respectively.

Gas-phase generation and infrared spectroscopy of metastable OP-SCN molecule.

An attempt has been made to generate the metastable phosphorus (III) oxythiocyanide molecule, OP-SCN for the first time by an on-line process using the vapor flow of phosphorus (III) oxychloride, OPCl passed over heated AgSCN at 520 degrees C. The products have been characterized by their IR spectra; values for v1 of 2055 cm(-1) (C[triple bond]N stretch), v2 of 1365 cm(-1) (O=P stretch), v3 of 720 cm(-1) (C-S stretch) and v7 of 680 cm(-1) (P-S stretch) have been obtained.