CRASY data

CRASY data description, data-sets, and data analysis guide. <div><br></div><div>The data-sets correspond to the continuously sampled data and sparsely sampled data show in the manuscript "Mass-correlated Rotational Raman Spectra with High Resolution, Broad Bandwidth, and Absolute Frequency Accuracy" (to be published).<div><br></div><div>Data-sets contain mass-CRASY data (zipped): </div><div> - Oct14_09.54-short (short data sample for testing)</div><div> - Aug11_20.57 (continuous sampling data)</div><div> - Dec16_20.15 (sparse sampling data)</div><div><br></div><div>Refer to the CRASY data format description to understand the data file contents.</div><div><br></div><div>Refer to the Python script to see an example of how the data can be accessed.</div><div><br></div><div>Contact the authors if you require further information.<br> <div>-------------------------------<br></div><div><div>Introduction of CRASY</div><div>-------------------------------</div><div>To understand the nature of CRASY measurements, refer to [Schroter C, Kosma K, Schultz T (2011) Crasy: Mass- or electron-correlated rotational alignment spectroscopy. Science 333:1011-1015.]</div><div>CRASY data consists of spectroscopic data (spectroscopic axis 1, e.g., photoionization mass spectra), measured as function of delay time relative to the excitation of a rotational wave packet. Signal modulations due to the wavepacket evolution contain information about rotational transitions encoded in the wave packet. Fourier-transformation of the signal modulations reveal rotational spectra (spectroscopic axis 2) that are inherently tied to the observed properties along spectroscopic axis 1. </div><div><br></div><div>------------------------------------------<br></div><div><div><div>CRASY data format description</div><div>------------------------------------------</div></div></div><div>A CRASY data-set consists of multiple files stored in a directory or zip file. Filenames denote the file content. I use Regex expressions to specify the information encoded in the filenames:</div><div>TS_[\s]+\d: measurement number \d (incrementing for each delay step)</div><div>*r\d*: repeat number \d (only relevant for sequential scans)</div><div>*w\d*: label for alignment signal (w1) and unaligned reference signal (w2)</div><div> (only present in scans measuring unaligned reference signal)</div><div><br></div><div>*.hdr files hold header information:</div><div>Line 1: Data acquisition program name</div><div>Line 2: Current delay time in ps</div><div>[Note the delay stage is: Physik Instrumente, MD-531, 16x folded beam path]</div><div>Line 3: Number of laser shots (signal was summed for this n.o.l.s.)</div><div>Line 5: Date and time of measurement start</div><div>Line 6,7: Obsolete detector parameters</div><div>Line 8: Digitizer time-of-flight acquisistion delay (in ns)</div><div>Line 9: Digitizer time-of-flight acquisition range (in ns)</div><div>[Note: The digitizer is a Fast Comtech 7886 card, the actual acquisition range is not identical to the set range. The acquisition bin width is 500 ps.]</div><div>Line 10-12: Obsolete scan and calibration parameters</div><div>Line 13-19: Environmental parameters</div><div>Line 21,22: Motorized laser mirror position (tracking of molecular beam)</div><div>Line 23: Number _n_ of oscillator jumps (delay += n/Osc_freq for each)</div><div>Line 24: Oscillator frequency</div><div><br></div><div>*.int files hold spectra (e.g., time-of-fligh mass spectra):</div><div>First 10 bytes denote the size (bytes) of the inflated spectrum.</div><div>The remaining data contains the spectrum in zlib compressed format, 16-bit bins.</div><div>Inflate using zlib library (; function 'uncompress'), or zlib.decompress in Python.</div></div><div><br></div></div></div>