Guanylurea(1+) hydrogen phosphite: a novel promising phase-matchable material for second harmonic generation

(2-Azoniaethyl)guanidinium dichloride – A promising phase-matchable NLO material employing a simple hydrogen bond acceptor in its structure

“…The choice of this basis set was due to its flexibility and the fact that diffuse p function on the hydrogen atoms tends to compensate the anharmonic effects of the CH and NH stretches [28]. Furthermore, this basis set allows for a direct comparison with the results of previous studies [18,19,29]. The geometry optimisations, also yielding the molecular energies, were followed by calculations of the first hyperpolarisability components ( Table 1).…”

“…In addition to salts resulting from inorganic and organic acids and unsubstituted guanidine [13][14][15], there have been reported several examples of unique crystalline materials based on guanidine derivatives such as arginine salts [16] showing excellent NLO properties as well as interesting molecular crystals resulting from biguanide [7,17], carbamoylguanidine [18,19] and aminoguanidine [20,21]. The attractiveness of this type of materials arises mainly from various v (2) and v (3) nonlinear laser effects they often exhibit [12,22].…”

Novel Salts of 2,4-Diaminoquinazoline: Searching for Materials for Second Harmonic Generation Based on a Promising Polarizable Cation

“…The static total hyperpolarizability b tot of the quin(1?) cation (1.05 9 10 -30 esu) is comparable to the results of a similar computation concerning the standard molecule of urea (B3LYP/6-311G: b tot = 0.78 9 10 -30 esu) [13] and so the cation can be considered as a promising carrier of NLO properties. Nevertheless, the behaviour of the final material strongly depends on its structure assembly, especially on the positioning of those molecules that can be sources of the desired property.…”

“…Measurements of SHG efficiency at 800 nm were performed by the modified powder technique [13] with 80 fs laser pulses generated at an 82 MHz repetition rate by a Ti:sapphire laser (Tsunami, Spectra Physics) with a measurement of the back-scattered laser light intensity at 400 nm by a grating spectrograph with diode array (InstaSpec II, Oriel). The SHG efficiencies obtained from samples of particle size 75-100 lm were compared with that of KDP (i.e.…”

“…In those materials, cations of, e.g., substituted triazoles [10], biguanides [11], guanidines [12] or guanylurea [13] serve as carriers of the desirable NLO properties. Their counterions play an important role in the final structure assembly by forming a system of hydrogen bonds that protects against unfavourable centrosymmetric arrangement of organic molecules [6].…”