DOI: 10.6084/m9.figshare.5886406.v1
title: CRASY data

description: CRASY data description, data-sets, and data analysis guide. <br>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).<br>Data-sets contain mass-CRASY data (zipped): - Oct14_09.54-short (short data sample for testing) - Aug11_20.57 (continuous sampling data) - Dec16_20.15 (sparse sampling data)<br>Refer to the CRASY data format description to understand the data file contents.<br>Refer to the Python script to see an example of how the data can be accessed.<br>Contact the authors if you require further information.<br> -------------------------------<br>Introduction of CRASY-------------------------------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.]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. <br>------------------------------------------<br>CRASY data format description------------------------------------------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:TS_[\s]+\d: measurement number \d (incrementing for each delay step)*r\d*: repeat number \d (only relevant for sequential scans)*w\d*: label for alignment signal (w1) and unaligned reference signal (w2) (only present in scans measuring unaligned reference signal)<br>*.hdr files hold header information:Line 1: Data acquisition program nameLine 2: Current delay time in ps[Note the delay stage is: Physik Instrumente, MD-531, 16x folded beam path]Line 3: Number of laser shots (signal was summed for this n.o.l.s.)Line 5: Date and time of measurement startLine 6,7: Obsolete detector parametersLine 8: Digitizer time-of-flight acquisistion delay (in ns)Line 9: Digitizer time-of-flight acquisition range (in ns)[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.]Line 10-12: Obsolete scan and calibration parametersLine 13-19: Environmental parametersLine 21,22: Motorized laser mirror position (tracking of molecular beam)Line 23: Number _n_ of oscillator jumps (delay += n/Osc_freq for each)Line 24: Oscillator frequency<br>*.int files hold spectra (e.g., time-of-fligh mass spectra):First 10 bytes denote the size (bytes) of the inflated spectrum.The remaining data contains the spectrum in zlib compressed format, 16-bit bins.Inflate using zlib library (https://www.zlib.net/; function 'uncompress'), or zlib.decompress in Python.<br>