Abstract-Evaluation of hydrogen-bonding distance in organic nonlinear optical crystals for high-output terahertz-wave generation

• Takeshi Matsukawa^a,  
• Akinori Hoshikawa^a, 
• Yoshihisa Ishikawa^b, 
• Toru Ishigaki^a

• ^a Frontier Research Center for Applied Atomic Sciences, Ibaraki University, 162-1 Shirakata, Tokai, Ibaraki, 319-1106, Japan
• ^b Institute of Material Structure Science, KEK Tokai, 203-1 Shirakata, Tokai, Ibaraki, 319-1106, Japan

Received 22 August 2016, Revised 4 January 2017, Accepted 5 January 2017, Available online 6 January 2017

http://www.sciencedirect.com/science/article/pii/S0022286017300261

The crystal structure of deuterated 4-dimethylamino-N-methyl-4-stilbazolium tosylate (DAST-d₂₆) was obtained by powder X-ray and neutron diffraction measurements. The scattering length density distributions of deuterium atoms were successfully obtained from neutron diffraction data using the maximum-entropy method. From the density distributions, we estimated the hydrogen-bonding distances, which contribute significantly to the vibrational modes of DAST at 1 THz. Inhibition of these hydrogen bonds could allow the development of new nonlinear optical materials with low THz absorption.

Abstract-Neutron crystal structure analysis of stilbazolium derivatives for terahertz-wave generation

Takeshi Matsukawa,*^a   Yukihiko Yoshida,^a   Akinori Hoshikawa,^a  Shuji Okada^b and   Toru Ishigaki^a  

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http://pubs.rsc.org/en/content/articlelanding/2015/ce/c5ce00107b#!divAbstract

CrystEngComm, 2015, Advance Article

DOI: 10.1039/C5CE00107B
Received 17 Jan 2015, Accepted 25 Feb 2015
First published online 03 Mar 2015

The refined crystal structure of stilbazolium derivatives was determined by neutron diffraction. The interatomic distances between the cation and the anion increased when the 4-position of the benzenesulfonate counteranion had a larger atom. The absorption coefficients of the 4-halobenzenesulfonate stilbazolium derivatives in the THz region became lower.