L-alanine Crystals Research Articles

Crystal structure-mechanical property relationship in succinic acid and L- alanine probed by nanoindentation

Establishing structure–mechanical property relationships is crucial for understanding and engineering the performance of pharmaceutical molecular crystals. In this study, we employed nanoindentation, a powerful technique that can probe mechanical properties at the nanoscale, to investigate the hardness and elastic modulus of single crystals of succinic acid and L-alanine. Nanoindentation results reveal distinct mechanical behaviors between the two compounds, with L-alanine exhibiting significantly higher hardness and elastic modulus compared to succinic acid. These differences are attributed to the underlying variations in molecular crystal structures − the three-dimensional bonding network and high intermolecular interaction energies of L-alanine molecules leads to its stiffness compared to the layered and weakly bonded crystal structure of succinic acid. Furthermore, the anisotropic nature of succinic acid is reflected in the directional dependence of the mechanical responses where it has been found that the (111) plane is more resistant to indentation than (100). By directly correlating the nanomechanical properties obtained from nanoindentation with the detailed crystal structures, this study provides important insights into how differences in molecular arrangements can translate into different macroscopic mechanical performance. These findings have implications on the selection of molecular crystals for optimized drug manufacturability.

Investigating the molecular crystals of L-Alanine, DL-Alanine, β-Alanine, and Alanine hydrogen chloride: Experimental and DFT analysis of structural and optoelectronic properties

In this study, DFT calculations were employed to assess and contrast the structural, electronic, and optical characteristics of five alanine crystal forms. The Perdew-Burke-Ernzerhof (PBE) generalized gradient approximation (GGA) with the Tkatchenko-Scheffler dispersion correction scheme was employed and compared to the PBE functional and the local density approximation (LDA) without dispersion correction. Experimentally, alanine crystal powders were characterized through X-ray diffraction (XRD) and UV–VIS absorption spectrum. Additionally, UV–VIS absorption measurements were performed on L-α-alanine, DL-alanine, β-alanine, and alanine hydrochloride solvated in water. Significant deviations (>10%) were observed between the experimental crystal lattice parameters and those predicted by the GGA and LDA methods. Incorporating dispersion correction into the GGA functional improved prediction accuracy. Additionally, time-dependent DFT (TD-DFT) computations using the polarizable continuum model were conducted to analyze the UV/VIS absorption spectrum of α-, β-, DL-, and hydrogen chloride alanine in water and interpret experimental data. Different alanine crystals exhibited substantial anisotropic electronic and optical properties, including effective masses, absorption, and dielectric function. The L-α-HCl structure displayed the smallest band gap (4.67 eV), suggesting its suitability for applications such as L-α/L-α-HCl/L-α quantum well structures. The main effective masses of electrons and holes were also determined for each crystal for a better understanding of their electronic transport properties.

Impact Of Shock Waves on Structural and Optical Properties of Li2so4.H2o Doped L-Alanine Single Crystals for High Pressure and Temperature Applications

The current study discusses the impact of shock wave of Mach number 1.7 on structural, molecular and optical properties of Li2SO4.H2O doped L-Alanine single crystals. PXRD, Raman spectral results confirm that the test crystal does not undergo any crystallographic phase transitions and conformational transitions against the shock wave. Optical micrographs and UV-Visible analysis communicate the subtle morphological changes and optical properties which is not significantly changed by shock wave. The results of crystallographic studies provide the strong proof that the crystal has molecular stability and a stable crystallographic structure against the impact of applied shock waves and suitable for a wide range of uses in aerospace applications.

Growth, structural, optical, thermal and terahertz time-domain spectroscopy of l-alanine single crystal: A potential amino acid based nonlinear optical material

In our present work, we focused on the terahertz (THz) based characterization of a very efficient organic nonlinear optical (NLO) single crystal of l-alanine (LA). Using the well-known slow evaporation solution growth method (SEST), an optically transparent amino acid-based LA crystal was effectively grown at room temperature. The structural information of the titled crystal was analyzed using powder X-ray diffraction (PXRD) which confirms the space group P212121 and orthorhombic structure of the crystal. Chemical etching of an as-grown single crystal was analyzed to identify the growth patterns. Fourier transform infrared (FTIR) and FT-Raman spectrometry were used to figure out the major functional groups that were present in the ingot crystal. The optical behaviour of LA crystal was observed through UV–Vis and Photoluminescence (PL) spectroscopies. The single crystal was found to have high transmission values over a wide range of wavelength. The PL results revealed that the main emission happens at 474 nm. Thermal stability of the titled compound was acquired by thermo-gravimetric and the differential thermo-gravimetric (TG-DTG) analysis. Open and closed aperture Z-scan measurements were used to analyze the third order nonlinear behavior of the as-grown sample using a femtosecond Ti-sapphire laser. To analyze the absorption peaks behavior Terahertz time-domain spectroscopy (THz-TDS) was also performed in the range 0.2–2.0 THz. The above study shows variation in absorption coefficient and refractive index at THz frequencies.

Characterization of Mass Transfer within the Crystal-Solution Boundary Layer of l-Alanine {120} Faces Using Laser Interferometry during Growth and Dissolution.

Crystallization and dissolution are important processes to consider in drug development as well as many other industrial processes. Many current growth and dissolution models are based on bulk solution properties and do not implicitly consider concentration variation close to the crystal surface-solution interface and how this is mediated by solute diffusive mass transfer. Solution boundary layer thickness and concentration distribution, for the {120} crystal habit face of single crystals of l-alanine in saturated aqueous solutions during both growth and dissolution processes, is measured as a function of super/undersaturation using a Mach-Zehnder optical interferometer system. Further analysis allows determination of the diffusion coefficient and mass flux within the boundary layer as well as whether the processes are controlled by mass transfer or crystal interfacial kinetics. The measurement of this study revealed that the {120} face was not saturated at its surface during growth or dissolution meaning both processes were somewhat limited by their crystal interfacial kinetics. Growth was limited by crystal interfacial kinetics at all supersaturations to the same degree, whereas dissolution had a mixed dependency on crystal interfacial kinetics and mass transfer at lower undersaturations becoming more limited by mass transfer at higher undersaturations. Boundary layer thickness increased with super/undersaturation but to a lesser degree than the increase in the concentration difference between the crystal surface and bulk solution leading to a higher mass flux of solute molecules through the boundary layer. At the same relative super/undersaturation mass flux of solute molecules was faster during dissolution which was concurrent with its increased surface to bulk solution concentration difference and boundary layer thickness.

Crystal growth and properties of pure L-alanine and boric acid doped L-alanine nonlinear optical single crystals for frequency conversion

Crystal growth and properties of pure L-alanine and boric acid doped L-alanine nonlinear optical single crystals for frequency conversion

Synthesis, growth and characterization of magnesium chloride doped L-alanine cadmium chloride single crystal: For nonlinear optical application

The aim of this research was to synthesize and characterize pure and magnesium chloride (MgCl2) doped L–alanine cadmium chloride (LACC) single crystals. Pure and MgCl2 doped LACC single crystals were synthesized by solution method with slow evaporation solution growth technique at room temperature. The single crystal X-ray diffraction studies of pure, 1 and 2 mol% MgCl2 doped LACC single crystals revealed monoclinic crystal structure with C2 space group. The optical properties of pure and MgCl2 doped LACC single crystals investigated by UV–VIS/NIR spectrometer confirmed that the crystals were transparent in the wavelength range of 230-1100 nm. The optical band gap energy of pure and doped LACC single crystals were found to have the same value of 5.4 eV. The energy-dispersive X-ray analysis indicated the incorporation of magnesium and chlorine atoms in LACC single crystal. The second harmonic generation efficiency of 1 and 2 mol% MgCl2 doped LACC crystals were analyzed by Kurtz-Perry powder technique and found to be 1.75 and 2 times greater than that of the standard potassium dihydrogen phosphate crystal, respectively.

Influence of glycine and ammonium dihydrogen phosphate on their growth and characterization of l-Alanine single crystal for nonlinear optical applications

A non-linear optical single crystal of l-Alanine has been synthesized using the glycine and l-Alanine doped with various concentration of ammonium dihydrogen phosphate (ADP) (0.25, 0.30, 0.35 & 0.45 M%) through slow evaporation technique at ambient temperature. The characterization of single and powder XRD crystal reveals their crystal structure, lattice parameters and various reflecting planes. Different vibration modes of functional groups in the crystal can be identified by FTIR. The optical transmission property and their corresponding band gap value were determined by UV–Vis study. Thermal stability and melting point were investigated using TG-DTA analysis. Vickers micro hardness study used to find out the mechanical strength and Meyer's index value ‘n’ of the crystal. Dielectric constant and dielectric loss response curves were plotted over the frequency range from 50 Hz to 1 MHz. The existence of nonlinear property produces the SHG efficiency that is 0.75 times higher than KDP through the Kurtz-Perry powder technique.

Studies on the growth aspects of L-alanine and lithium sulfate doped L-alanine single crystals for electro-optic applications

Single crystals of L-alanine and Lithium sulfate doped L-alanine crystals were successfully grown by the slow evaporation method. The powder XRD studies were used to analyze the crystalline nature of the crystals. ICP analysis confirms the presence of lithium in the grown L-alanine crystal. The optical bandgap of grown crystals was measured by UV–Vis spectroscopy, and different functional groups present in the grown crystals have been identified by the FTIR spectral analysis. The dielectric studies of the grown crystals were performed at different temperatures as a function of the frequency. The photoconductivity study contributed its positive photoconducting nature. The second harmonic generation for the grown crystal was confirmed by the Kurtz–Perry technique.

Miniaturized draft tube baffle crystallizer for continuous cooling crystallization

Industrial draft tube baffle (DTB) crystallizers are well known and can be found in many applications; however, DTBs are rarely investigated on the laboratory scale. A miniaturized DTB for continuous cooling crystallization with integrated fine-grain dissolution was designed, set up, and characterized. A typical DTB from the m³-scale was scaled down to 2 L filling volume to enable lab-scale investigations concerning process development. The fluid dynamic behavior was determined with suspension performance and residence time of the liquid and solid phase. Five different start-up variations were investigated for cooling crystallization of l-alanine dissolved in water. Hurdles with the periphery were identified, different start-up variations were tested, and the promising ones were determined. It was found that the residence time of the solid phase is shorter than the liquid phase due to the classifying behavior of the DTB, i.e., the crystal residence time could be shortened by decreasing the stirrer speed. The investigations show the potential of the miniaturized DTB for the process development of continuous procedure and small-scale production.

Growth, physiochemical and NLO properties study of novel L-alanine tri-sodium citrate single crystal

A single crystal of nonlinear optical (NLO) of L-Alanine Trisodium Citrate (LATSC), an optically transparent crystal with a dimension 38 × 27 × 7 mm3, was grown by way of solvent evaporation technique. Through the result of crystal diffraction, it is confirmed that LATSC fit into the noncentrosymetric orthorhombic space group crystal system. The W-H method was used to find the crystallographic distortion, crystalline size and strain using the powder diffraction results. The FTIR study proves the presence of necessary functional groups through their respective diverse modes of vibrations. The melting point of 265.9 °C was noticed from thermal studies. The second harmonic generation (SHG) efficiency of LATSC is half of the reference KDP. The optical absorption study and associated optical parameters of the crystal were calculated using UV visible spectroscopy. The extended transparency for the incident light and the direct band gap of 4.23 eV along with the optical susceptibility of 3.519 were perceived. The hardness test revealed the considerable mechanical strength, moderate stiffness constant and yield strength of the crystal.

Local Piezoelectric Properties of Doped Biomolecular Crystals.

Piezoelectricity is the ability of certain crystals to generate mechanical strain proportional to an external electric field. Though many biomolecular crystals contain polar molecules, they are frequently centrosymmetric, signifying that the dipole moments of constituent molecules cancel each other. However, piezoelectricity can be induced by stereospecific doping leading to symmetry reduction. Here, we applied piezoresponse force microscopy (PFM), highly sensitive to local piezoelectricity, to characterize faces of a popular biomolecular material, α-glycine, doped with other amino acids such as L-alanine and L-threonine as well as co-doped with both. We show that, while apparent vertical piezoresponse is prone to parasitic electrostatic effects, shear piezoelectric activity is strongly affected by doping. Undoped α-glycine shows no shear piezoelectric response at all. The shear response of the L-alanine doped crystals is much larger than those of the L-threonine doped crystals and co-doped crystals. These observations are rationalized in terms of host–guest molecule interactions.

Activation Volume of the Elastic–Plastic Transition in Molecular Crystals

Nanoindentation experiments with a spherical indenter tip were performed on the major faces of l-alanine, p-nitroaniline, dl-tartaric acid, and sulfathiazole single crystals to measure the load at which an elastic-to-plastic deformation transition occurs, which is marked by a discrete displacement burst or pop-in. Large data sets (containing more than 100 points each) of the experimentally measured first pop-in loads, P1, were generated. By assuming that the statistical distribution in P1 is a consequence of the thermal fluctuations affecting the nucleation rate of incipient plastic events underneath the indenter, the activation volumes, Λ, for the elastic–plastic transition are determined. For the four molecular crystals examined, Λ values vary between 106 and 173 Å3, which are more than an order of magnitude than those in crystalline metals. However, they are similar to the molecular volume, Ψ. A linear relationship between Λ and Ψ suggests that the plastic deformation in molecular crystals is intimately linked to the size of the molecules. These results are discussed in the context of slip planes and their orientations to the indentation direction, interplanar spacings, intermolecular interactions, etc.

Growth, Characterization and NLO Property Study of Doped L-Alanine Crystal

Growth, Characterization and NLO Property Study of Doped L-Alanine Crystal

Growth, Nonlinear Optical, Electrical, Mechanical and Dielectric Properties of Zinc Sulphate Doped L-Alanine Single Crystal for Optoelectronic Applications

Zinc sulphate added L-alanine (LAZS) crystals were obtained from solvent evaporation of solution method. The obtained samples were taken for diverse characterizations tool such as, XRD, functional group identification, optical transparency, simultaneous thermal analysis, dielectric, hardness and second harmonic generation studies. Crystal diffraction study proves that LAZS crystal fit into orthorhombic system and having space group P212121. FTIR confirms presences of various functional groups present in the sample. The thermal study infers that LAZS is steady up to 288 ºC. High transmittance and extended transparency of LAZS is noticed from linear optical study. The calculated hardness values were found to be considerable and the dielectric parameters are noticed characteristically followed by NLO study.

Seed supported solution growth and characterization of L-alanine single crystals for optoelectronics

The large growth of L-alanine single crystal (size = ~18 × 12 × 12 mm3) was achieved by seed supported solution growth technique for the first time. The structure and vibrational modes of the crystal were confirmed by X-ray diffraction (XRD) and FT-Raman analyses, respectively. UV–Vis-NIR absorbance and transmittance measurements were carried out and Tauc’s rule is used to calculate energy gap for the grown crystal and found to be lie within 5.26–5.36 eV. The grown crystal is of high transparency between 80 and 89%, and the energy gap makes it useful for optoelectronic devices. The mechanical strength and chemical etching studies were also carried out and discussed. The present load independent hardness values along different faces of L-alanine crystal are noted ~30, 48, 50 and 65 kg/mm2, respectively, which indicates that (202) face showing higher hardness value compare to all the faces. The etch pit density was observed to be ~4 × 102/cm2. Furthermore, dielectric and electrical studies were also done. The facile and low-cost growth, high optical transparency, energy gap, microhardness, dielectric and electrical of the grown crystal indicates that it is suitable for optoelectronic devices.

Unidirectional crystal growth of L-alanine doped triglycine sulphate crystals along [010] polar direction in ferroelectric and paraelectric temperature ranges, and their comparative characterizations

Good quality, large size (010) polar face oriented ferroelectric single crystals of l-alanine doped triglycine sulphate (LA-TGS) were grown by unidirectional solution growth technique in two temperature regimes on either side of its Curie temperature (Tc). The growth conditions were optimized to obtain LA-TGS crystals of length = 40 mm, diameter = 30 mm below Curie temperature (Tc), and length = 50 mm, diameter = 15 mm above Curie temperature, with growth rates of 1.3 and 3.0 mm/day, respectively. Powder XRD was performed for phase confirmation and DTA for phase transition temperature determination, and compared with data of undoped TGS crystal. Crystal grown below Tc has almost same dislocations density, two times higher piezoelectric d33 coefficient, and three times lower dielectric permittivity as compared to the crystal grown above Tc, showing its better device potential. The UV-Vis-NIR transmittance of the two crystals was ≥80 %, showing their good optical quality.

Influence of Zirconium Nitrate doping on the properties of l-Alanine crystal for nonlinear optical applications

Nonlinear optical single crystals of pure l-Alanine (LA) and Zirconium Nitrate-doped l-Alanine (ZNLA) were grown by low-temperature solution growth slow evaporation technique at room temperature. Single crystal and powder XRD confirms the orthorhombic structure. The average crystallite size and lattice strain are 53.21 nm and 0.0048 for LA and 62.17 nm and 0.0041 for ZNLA. FTIR reveals the presence of functional groups in the grown crystal. The optical analysis confirms the high transparency, the obtained direct and indirect transition bandgap of LA and ZNLA are 5.4 eV, 4.84 eV and 5.32 eV, 4.11 eV. The dielectric constant and dielectric loss of the gown materials are low at high frequencies. The relative second harmonic efficiency of l-Alanine and Zirconium Nitrate-doped l-Alanine are 1.15 and 1.47 times higher than that of KDP. The magnetic parameters were identified with VSM analysis. The thermal stability of LA and ZNLA single crystals was found stable up to 193.5 35 °C and 248.35 °C for ZNLA. Photoconductivity reveals that both the material LA and ZNLA have negative photoconductivity nature.

Influence of bismuth nitrate doping towards the characteristics of L-Alanine nonlinear optical crystals

In the present study, an amino acid derivatives, L-alanine (LA) and Bismuth nitrate-doped L-alanine (BNLA) crystals were grown by the slow evaporation technique. The crystal structure and quality of the grown crystal were examined by single-crystal X-ray diffraction (XRD) and powder XRD. The X-ray diffraction analysis of LA and BNLA crystals confirmed the orthorhombic crystal system without any internal structural grain boundaries. The optical properties of the LA and BNLA crystals have been determined using UV-Visible spectroscopy and Photoluminescence (PL). The second harmonic generation (SHG) efficiency of the crystal was measured using Kurtz powder technique. The dielectric constant measurement was performed at room temperature for different frequencies. Photoconductivity tests show that the LA and BNLA crystals have negative photoconductivity value. On testing of the retentivity or remanent magnetization, the BNLA crystal has increased values as compared to the pure LA crystals, in addition to the observation of changes in coercivity. Further, the observation of maximum intensity peak for the BNLA crystal at 346.9 nm pointed out that the crystal has blue fluorescence emission. The third-order nonlinear optical properties of the grown crystal were studied using Z-scan technique. The enhancement in nonlinear refractive index and third-order NLO susceptibility value shows that the grown BNLA crystals may be of good quality and less in defect than that of pure LA crystals.

In fact, L-alanine

Abstract It is shown that two papers of Shanmuga Sundaram et al reporting on the growth of “L-alanine potassium nitrate” (LAPN) and “L-alanine sodium nitrate” (LASN) crystals are completely erroneous. In fact, only crystals of L-alanine were obtained in both cases.