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At least 1,189 records · Page 66Linked to original sources
PubMed2006

Structural, spectral, linear and nonlinear optical properties of new nonlinear optical L-histidinium trichloroacetate crystals.

Single crystals of a new histidinium salt: L-histidinium trichloroacetate {abbreviated as LHTCA; [(C(3)N(2)H(4))CH(2)CH(NH(3))(CO(2))](+)CCl(3)COO(-)} were grown by slow evaporation of an aqueous solution at room temperature. The compound crystallizes in a non-centrosymmetric space group P2(1) of monoclinic system with cell parameters a=5.4505(18) A, b=25.769(8) A, c=9.210(2) A and beta=99.98(2) degrees. The vibrational structure of the compound confirms the presence of various functional groups in the molecule. The UV-vis-NIR spectrum shows a good transparency in the whole of the region from ultraviolet to near IR. The Kurtz powder SHG measurement confirms the frequency doubling of the crystal. Thermal behaviour of the crystals has been investigated by DSC analysis. These preliminary results suggest that LHTCA crystal can act as a potential and promising candidate for frequency doubling applications even from the near UV region to the near IR.

Crystallization↗
PubMed2003

Spectroscopic and optical studies on pure and doped single crystals of sulphate-mixed L-arginine phosphate monohydrate--a nonlinear optical crystal.

Single crystals of pure and transition metal ions (Cu(2+) and VO(2+))-doped L-arginine sulpho phosphate monohydrate (sulphate-mixed L-arginine phosphate monohydrate, abbreviated as LASP) have been grown by solvent evaporation of the saturated aqueous solution at room temperature and characterized by single-crystal XRD, FT-IR, UV-Vis-NIR and EPR (single-crystal rotation) spectral studies. Kurtz powder technique shows an enhanced second harmonic generation (SHG) efficiency for LASP and its doped analogues than pure LAP. The EPR studies on LASP:VO(2+) reveal that the in-plane sigma-bonding is moderately covalent and the out-of-plane pi-bonding is highly covalent, which could be attributed to the cause of enhanced powder efficiency.

Arginine↗
PubMed2005

Observation of the c1A1 state of methylene by optical-optical double resonance.

We report the observation of the rotationally resolved spectrum of the c1A1 state of CH2 via sequential single-photon absorptions at visible and near-infrared wavelengths. Direct absorption from the lowest singlet state a1A1 to c1A1 occurs in the near UV, but it is weak because it corresponds to a two electron transition between the dominant single configuration approximations to the electronic wave functions. Some absorption lines in the c-a system were originally reported in 1966 [G. Herzberg and J. W. C. Johns, Proc. R. Soc. London, Ser. A 295, 107 (1966)], but the weak spectra could not be assigned at the time. Interest in the c1A(1) state was rekindled by recent ab initio results [S. N. Yurchenko, P. Jensen, Y. Li, R. J. Buenker, and P. R. Bunker, J. Mol. Spectrosc. 208, 136 (2001)] which prompted the present work. The new spectra provide accurate energies for rotational levels in the v2linear =11,l = 1 level of the state, and permit assignment of most of the line positions measured by Herzberg and Johns. The double-resonance technique used may be easily extended to the measurement of lower rovibrational levels in the electronic state and possibly also to access the d1A2 state which is theoretically expected to lie at similar energies but, for symmetry reasons, is not accessible from the lowest singlet state in a single electric-dipole transition.

Journal Article↗