Analytical angular solutions for the atom–diatom interaction potential in a basis set of products of two spherical harmonics: two approaches

We present general analytical expressions for the matrix elements of the atom–diatom interaction potential, expanded in terms of Legendre polynomials, in a basis set of products of two spherical harmonics, especially significant to the recently developed adiabatic variational theory for cold molecular collision experiments [J. Chem. Phys. 143, 074114 (2015); J. Phys. Chem. A 121, 2194 (2017)]. We used two approaches in our studies. The first involves the evaluation of the integral containing trigonometric functions with arbitrary powers. The second approach is based on the theorem of addition of spherical harmonics.

Stereodynamic control of cold rotationally inelastic CO + HD collisions

Quantum control of molecular collision dynamics is an exciting emerging area of cold collisions. Co-expansion of collision partners in a supersonic molecular beam combined with precise control of their quantum...

Enzyme Kinetics Study for Heterogeneous System of Pretreated Kenaf Hydrolysis

The peculiarity of spatially restricted diffusion and molecular collision processes results in considerable contrast in a reaction between the reactant and catalyst in the heterogeneous system from its corresponding homogeneous structure. The identification of the enzymatic hydrolysis process of pre-treated kenaf and to convert it into simple sugars employing a systematic kinetic investigation is the aims of this study. The influence of substrate concentration on xylanase hydrolysis was performed in water bath shakers. In-house recombinant xylanase expressed in Pichia pastoris was used for the hydrolysis at pH 4.0 in 50 mM sodium citrate buffer with 200 rpm agitation. Modified Prout-Tompkins equation was used for the heterogeneous substrate hydrolysis. The results obtained show that temperature simultaneously influenced the time dependency of the reducing sugar yield. Dependence of the enzymatic rate of reaction can be calculated effectively on the conversion of substrates over different temperatures. The activation energy needed for pretreated kenaf hydrolysis was among the least compared to other lignocelluloses, which was only 25.15 kJ/mol. In conclusion, the exponential kinetic equation by the Modified Prout-Tompkins equation offers a solid understanding of xylanase hydrolysis on the pretreated kenaf. Thus, the prediction of the degree of hydrolysis required at the predetermined temperature and time values used can be quickly and precisely determined.

Aggregation Behavior of Acylated Pepsin-Solubilized Collagen Based on Fluorescence Spectrum Technology

The aggregation behavior of collagen-based materials plays an important role in their processing because it could affect their physicochemical properties. Based on the intrinsic fluorescence characteristic of tyrosine, fluorescence spectrum technology was used to investigate the aggregation state of the acylated collagen molecules in aqueous solution. The results showed that the aggregate degree of the acylated collagen was higher than that of the native collagen due to the hydrophobic interaction. With the increase of concentrations of the acylated collagen or at NaCl higher than 40 mmol/L, the aggregate degree of the acylated collagen molecules increased. When the pH was close to the isoelectric point of the acylated collagen, the hydrophobic interaction and the hydrogen bond helped to increase the aggregation degree. However, with the increase of temperature (10–70 ℃), the aggregation state of the acylated collagen decreased gradually due to the quenching, the molecular collision, and the broken of hydrogen bonds. Furthermore, two-dimensional correlation spectroscopy (2D-COS) showed that the response order was 360 > 305 nm at various acylated collagen and NaCl (>40 mmol/L) concentrations, while the response order was 305 > 360 nm when the pH value was increased from 5.0 to 9.0. Temperature-dependent 2D-COS showed there were four bands that occurred and the response order was listed as follows: 293 > 305 > 360 > 420 nm. In brief, the results might provide an important guide for molding processes of the acylated collagen.

A parallelized molecular collision cross section package with optimized accuracy and efficiency

A new parallelized calculation package predicts collision cross sections with high accuracy and efficiency.

Special Issue on Atomic and Ionic Collisions with Formation of Quasimolecules

Many areas of science today, like atomic and molecular physics, nuclear physics, astrophysics, laboratory plasma research etc., depend on data for ionic, atomic, and molecular collision processes. The purpose of the Special Issue “Atomic and Ionic Collisions with Formation of Quasimolecules” in Atoms is to engage a broad community of researchers to consolidate knowledge, make new discoveries, and to continue the exchange of ideas.