Dmitry Strelnikov Roman Reusch and Wolfgang Krtschmer MaxPlanckInstitut

Dmitry Strelnikov, Roman Reusch and Wolfgang Krätschmer Max-Planck-Institut für Kernphysik, Heidelberg, Germany Systematics in the IR Absorptions of Odd Carbon Chains 21 st of June 2005, Columbus

Experimental Setup

Matrix-isolated carbon molecules Carbon vapor molecules as deposited in cryogenic Ne-, Ar- or Kr-matrices IR-spectra before and after annealing in Ar Chain growth by matrix annealing UV/Vis-spectra before and after annealing in Ar

Strategy ? □ Comparison of IR and UV/Vis absorptions of Cn in Ar and O 2 matrices □ Method´s test: Selective oxidation of Cn with known IR and UV/Vis absorption spectra □ Method´s application: Selective oxidation of Cn with unknown IR but known UV/Vis absorptions □ Looking for systematics in the IR spectra of long C 2 n+1 molecules

Cn absorbtions in Ar matrix, and O 2 matrices, UV-vis spectrum D. Forney, P. Freivogel, M. Grutter and J. P. Maier, J. Chem. Phys. , 1996

C Cnn absorbtions in in Ar O Ar 2 and matrix, O 2 matrices, IR spectrum A. Van Orden and R. Saykally; Chem. Rev. 1998

Isotopic substitution of matrix oxygen. The way to distinguish pure carbon molecules and oxides.

a □ Comparison of IR and UV/Vis absorptions of Cn in Ar and O 2 matrices ? □ Method´s test: Selective oxidation of Cn with known IR and UV/Vis absorption spectra □ Method´s application: Selective oxidation of Cn with unknown IR but known UV/Vis absorptions □ Looking for systematics in the IR spectra of long C 2 n+1 molecules

Selective LASER-induced oxidation of carbon chains in O 2 matrices. UV-vis Difference in absorption before and after LASER exposure IR

a □ Comparison of IR and UV/Vis absorptions of Cn in Ar and O 2 matrices □ Method´s test: Selective oxidation of C 9, C 11, C 13 a having known IR and UV/Vis absorption spectra ? □ Method´s application: Selective oxidation of Cn with unknown IR but known UV/Vis absorptions □ Looking for systematics in the IR spectra of long C 2 n+1 molecules

a □ Comparison of IR and UV/Vis absorptions of Cn in Ar and O 2 matrices □ Method´s test: Selective oxidation of Cn with a known IR and UV/Vis absorption spectra □ Method´s application: Selective oxidation of Cn a with unknown IR but known UV/Vis absorptions ? □ Looking for systematics in the IR spectra of long C 2 n+1 molecules

IR-absorptions of carbon molecules in Ar, 30 K Where are the (3 N-5)/2 IR-active modes ?

Intensities of infrared absorptions of long odd-numbered carbon chain molecules PM 3, DFT(b 3 lyp/6 -311 G(d)) - intensity of the k-th vibrational mode - dipole moment, xk, sk - Cartesian and normal coordinates, qi - Mulliken charges, Li, k – matrix of vibrational eigenvectors as columns ( )

Red and blue Ne-to-Ar (gas-to-Ar) matrixshifts of the totally alternating vibration for long odd-numbered carbon chains Cn in gas phase * * * - Prediction *

Conclusion The method of selective laser-induced oxidation works and turned out to be useful for the characterization of odd linear carbon chains. A regularity in the IR-absorptions of linear C 2 n+1 species was established.