P Johnsson et al 2009 J. Phys. B: At. Mol. Opt. Phys. 42 134017 doi:10.1088/0953-4075/42/13/134017
P Johnsson1, A Rouzée1, W Siu1, Y Huismans1, F Lépine2, T Marchenko3, S Düsterer4, F Tavella4, N Stojanovic4, A Azima4, R Treusch4, M F Kling5 and M J J Vrakking1
Show affiliationsHigh flux extreme ultraviolet (XUV) sources like the free electron laser (FEL) in Hamburg (FLASH) offer the possibility of diffractive imaging of small objects. Irrespective of whether the diffraction is based on the detection of photons or photoelectrons, it is required that the measurement is done in the reference frame of the molecule meaning that, for a sample of several molecules, it is necessary to pre-align the molecules in the sample. As a step towards performing molecular frame diffraction experiments, we report experiments on field-free molecular alignment performed at FLASH. The impulsive alignment induced by a 100 fs near-infrared laser pulse in a rotationally cold CO2 sample is characterized by ionizing and dissociating the molecules with a time-delayed XUV-FEL pulse. The time-dependent angular distributions of ionic fragments measured by a velocity map imaging spectrometer exhibit rapid changes associated with the induced rotational dynamics. The experimental results show hints of a dissociation process that depends nonlinearly on the XUV intensity.
33.80.Gj Diffuse spectra; predissociation, photodissociation
33.15.Mt Rotation, vibration, and vibration-rotation constants
33.80.Eh Autoionization, photoionization, and photodetachment
Issue 13 (14 July 2009)
Received 23 January 2009, in final form 6 March 2009
Published 12 June 2009
P Johnsson et al 2009 J. Phys. B: At. Mol. Opt. Phys. 42 134017
M Krug et al 2009 New J. Phys. 11 105051
M Fannes and J Wouters 2009 J. Phys. A: Math. Theor. 42 465308
C Cornaggia 2009 J. Phys. B: At. Mol. Opt. Phys. 42 161002
A N Grum-Grzhimailo et al 2009 J. Phys. B: At. Mol. Opt. Phys. 42 171002
Banamali Roy et al 2008 Phys. Scr. 2008 014046
T J Quinn 1999 Metrologia 36 77
N L S Martin et al 2009 J. Phys. B: At. Mol. Opt. Phys. 42 225201
Andrea Montanari et al J. Stat. Mech. (2008) P04004
I Vurgaftman et al 2009 New J. Phys. 11 125015