Düsseldorf 2007 – scientific programme

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MO: Fachverband Molekülphysik

MO 61: Quantum Control I

MO 61.1: Talk

Friday, March 23, 2007, 10:30–10:45, 6F

Excitation of C₆₀ with Temporally Shaped Laser Pulses: Coherent Heating of Nuclear Motion — •Claus Peter Schulz, Ihar Shchatsinin, Tim Laarmann, Nickolai Zhavoronkov, and Ingolf Volker Hertel — Max Born Institute, Max-Born-Str. 2a, 12489 Berlin-Adlershof, Germany

Femtosecond laser pulses tailored with closed-loop, optimal control feedback were used to optimise the C₂ evaporation from C₆₀ [1]. A characteristic pulse sequence results in significant enhancement of the C₅₀⁺ yield, a typical fragment of vibrationally hot C₆₀, in comparison with the response to a single pulse of the same energy and overall width. The separation between subsequent pulses is close to the vibrational period of the radial symmetric a_g(1) breathing mode. In a two-colour pump-probe experiment similar modulations were observed in the ion signal of multiply charges fragments. The observed period (80-127 fs) of this oscillation depends on the degree of ionisation and the deposited energy. Comparison with TDDFT calculations indicates that the shaped laser pulse excite giants oscillations in C₆₀, which prevails for several cycles.

[1] T. Laarmann, I. Shchatsinin, A. Stalmashonak, M. Boyle, N. Zhavoronkov, J. Handt, R. Schmidt, C. P. Schulz, and I.V. Hertel, Physical Review Letters, in press (2006)