Data scaling and temperature calibration in time-resolved photocrystallographic experiments

Abstract

Experiments in which structural changes in crystals are induced by pulsed-laser exposure involve an increase in sample temperature due to the dissipation of the deposited excess energy. The heat increase is especially pronounced when a large number of pulses is needed, as in pseudo-steady-state experiments conducted at conventional sources, but not negligible in synchrotron studies in which very short laser exposures may be adequate. The relative scaling of the light-ON and light-OFF data and the correction for temperature differences between the two sets are discussed.

Shedding Light on the Photochemistry of Coinage-Metal Phosphorescent Materials: A Time-Resolved Laue Diffraction Study of an AgI–CuI Tetranuclear Complex

“…k B ranged from 1.035 to 1.064 in the four data sets collected (Table S5, Supporting Information), which, in the classical harmonic limit, corresponds to a 3–6 K temperature increase, in good agreement with the slope of the photo-Wilson plot 107 obtained prior to the refinement. The refined population of the excited-state species ranged from 0.5 to 1.7% in the four data sets (Table S5, Supporting Information).…”

Time-resolved Laue diffraction of excited species at atomic resolution: 100 ps single-pulse diffraction of the excited state of the organometallic complex Rh2(μ-PNP)2(PNP)2·BPh4

“…Possible temperature differences are taken into account in the Laser program by introduction of a overall temperature-scale-factor k B which multiplies the experimental atomic displacement parameters (ADP’s). 13 However, in the current study temperature increases are moderate as single-pulse diffraction images were recorded k B factors averaged 1.23 for the 12 keV and 1.12 for the 15 keV experiments which were recorded with lower laser power; The excited-state populations averaged over each of the 3 sets are 6.6% (12 keV) and 4.7% (15 keV). Resulting GS and ES Rh–Rh bond distances are listed in Table 1.…”

Photocrystallographic Observation of Halide-Bridged Intermediates in Halogen Photoeliminations

“…48 On the basis of this analysis, laser heating warmed the single crystal of 1 from 15 to ∼250 K (Figure S18). The metrical parameters of 1 do not show significant temperature-dependent variation (Table S2), confirming that the difference map arises from photochemical, not thermal, effects.…”