Abstract
The absolute orientation of the local average polarization in relation to the main crystal growth direction has been investigated for channel-type inclusions of perhydrotriphenylene (PHTP) and five guests: N,N-dimethyl-3-nitroaniline (DMNA), 1-(4-nitrophenyl)-piperazine (NPP), 4-iodo-4′-nitrobiphenyl (INBP), 4-amino-4′-nitrostilbene (ANS) and N,N-dimethyl-4(4-nitrophenylazo)aniline (DNAA). For this we have used phase sensitive second harmonic generation microscopy (PH-SHM) and a crystal of 2-cyclooctylamino-5-nitropyridine (COANP) as a NLO reference material for which we know the absolute polarity from X-ray anomalous scattering. Bi-polar states of all five inclusion compounds have been confirmed. Application of PS-SHM revealed that the nitro groups preferably point into the direction of growth. The attributed molecular orientation is further on confirmed (PHTP/DNAA and PHTP/INBP) by scanning pyroelectric microscopy. Results from Monte Carlo (MC) simulations allow us to conclude that the fundamental energy parameter ΔEf driving stochastic polarity formation is larger than zero.
Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
