Accurate modeling of high-temperature hypersonic flows in the atmosphere requires consideration collision-induced dissociation molecular species and energy transfer between translational internal modes gas molecules. Here, we describe a study N2 + N2⟶N2 2N N2⟶4N nitrogen reactions using quasiclassical trajectory (QCT) method. The simulations used new potential surface for N4 system; is an improved version one that was presented previously. In QCT calculations, initial conditions were...

We present a global ground-state potential energy surface for N4 suitable treating high-energy vibrational-rotational transfer and collision-induced dissociation in N2–N2 collisions. To obtain the surface, complete active space second-order perturbation theory calculations were performed ground singlet state with an of 12 electrons orbitals maug-cc-pVTZ triple zeta basis set. About 17 000 ab initio data points have been calculated system, distributed along nine series N2 + geometries three...

Our ability to understand and simulate the reactions catalyzed by iron depends strongly on our predict relative energetics of spin states. In this work, we studied electronic structures Fe2+ ion, gaseous FeO 14 complexes using Kohn-Sham density functional theory with particular focus determining ground state these species as well magnitudes relevant spin-state energy splittings. The investigated in work have hexacoordinate geometries which seven are Fe(ii), five Fe(iii) two Fe(iv) complexes....

We present global potential energy surfaces for nine adiabatic electronic states of O3, namely, 1 1A′, 2 1A″, 3A′, 3A″, 5A′, and 5A″. These are the O3 that accessed in electronically collisions a ground-state triplet O2 molecule with O atom. The based on XMS-CASPT2 structure calculations dynamically scaled external correlation. active space has 12 electrons distributed 2p orbitals. fitted to analytic functions using many-body expansion where pairwise additive term is an accurate diatomic...

Quantitative simulations of electronically nonadiabatic molecular processes require both accurate dynamics algorithms and electronic structure information. Direct semiclassical is expensive due to the high cost calculations, hence it limited small systems, ensemble averaging, ultrafast processes, and/or methods that are only semiquantitatively accurate. The calculations can be made manageable if analytic fits data, such most conveniently carried out in a diabatic representation because...

We present global ground-state potential energy surfaces for the quintet and singlet spin states of O4 system that are suitable treating high-energy vibrational-rotational transfer collision-induced dissociation in electronically adiabatic, spin-conserving O2-O2 collisions. The based on MS-CASPT2/maug-cc-pVTZ electronic structure calculations with scaled external correlation. active space has 16 electrons 12 orbitals. cover nine kinds geometrical arrangements corresponding to dissociative...

Although there is a significant effort in the design of selective CDK9/CycT1 inhibitor, no compound has been proven to be specific inhibitor this kinase so far. The aim research was develop novel and phosphorus containing inhibitors. Molecules bearing phosphonamidate, phosphonate, phosphinate moieties were synthesized. Prepared compounds evaluated an enzymatic assay. most potent molecules tested cell-based toxicity HIV proliferation assays. Selectivity shortlisted against CDKs other kinases...

We present a global ground-state triplet potential energy surface for the N2O2 system that is suitable treating high-energy vibrational-rotational transfer and collision-induced dissociation. The based on multi-state complete-active-space second-order perturbation theory/minimally augmented correlation-consistent polarized valence triple-zeta electronic structure calculations plus dynamically scaled external correlation. In multireference calculations, active space has 14 electrons in 12...

We present a global ground-state potential energy surface (PES) for the triplet spin state of O4 that is suitable treating high-energy vibrational-rotational transfer and collision-induced dissociation in electronically adiabatic spin-conserving O2-O2 collisions. The based on MS-CASPT2/maug-cc-pVTZ electronic structure calculations with scaled external correlation; active space has 16 electrons 12 orbitals. was fitted by many-body approach an accurate O-O pairwise interaction fit to 10 180...

This paper presents molecular dynamics calculations of vibrational energy transfer and nonequilibrium dissociation in collisions. The interactions are modeled using nine potential surfaces corresponding to the , states, which govern electronically adiabatic collisions ground-electronic-state diatomic oxygen with atomic oxygen. Characteristic excitation times calculated over a temperature range rate coefficients . Vibrational relaxation rates, specific each PES, found vary by an order...

A potential energy surface (PES) for high-energy collisions between nitrogen molecules is useful modeling chemical dynamics in shock waves and plasmas. In the present work, we fit many-body (MB) component of ground-state PES N4 to an analytic function using neural networks (NNs) with permutationally invariant polynomials (PIPs). The fitting dataset system extension one used previously, extended 4859 new CASPT2 points 13 CCSD(T) reach a total 21 406 points. MB-PIP-NN required very complete...

The site-specific basicities of imatinib (Gleevec, a new signal transduction inhibitor drug chronic myeloid leukemia) and two its fragment compounds were quantitated in terms protonation macroconstants, microconstants, group constants by NMR−pH pH-potentiometric titrations. Sequential follows the N34, N11, N31, N13 order, which N11 N31 show commensurable basicity, but negligible intramolecular interaction. Fragment include "halves" imatinib, their moiety-specific confirm NMR-based sequence...

Simulations of electronically nonadiabatic processes may employ either the adiabatic or diabatic representation. Direct dynamics calculations are usually carried out in basis because energy, force, and state coupling can be evaluated directly by many electronic structure methods. However, although its straightforwardness is appealing, direct expensive when combined with quantitatively accurate theories. This generates interest analytically fitted surfaces to cut expense, but cuspidal ridges...

Potential energy surfaces for high-energy collisions between an oxygen molecule and a nitrogen atom are useful modeling chemical dynamics in shock waves. In the present work, we doublet, quartet, sextet potential that suitable studying of O2(3Σg−) with N(4S) electronically adiabatic approximation. Two sets developed, one using neural networks (NNs) permutationally invariant polynomials (PIPs) least-squares many-body (MB) method, where two-body part is accurate diatomic three-body expressed...

Creating analytic representations of multiple potential energy surfaces for modeling electronically nonadiabatic processes is a major challenge being addressed in various ways by the chemical dynamics community. In this work, we introduce new method that can achieve convenient learning (PESs) and their gradients (negatives forces) polyatomic system. This method, called compatibilization deep neural network (CDNN), demonstrated to be accurate and, even more importantly, automatic. The only...

This work presents two global triplet potential energy surfaces (PESs) for the high-energy reaction N2(X1Σ) + O(3P) → NO(X2Π) N(4S)—in particular, lowest 3A′ and 3A″ PESs. In order to obtain energies needed fitting analytic surfaces, we carried out multireference configuration interaction (MRCI) calculations based on wave functions obtained from state-averaged complete active space self-consistent field 2280 geometries three states 2298 states. The lowest-energy at each of these were then...

Direct nonadiabatic dynamics is used to study processes involving multiple electronic states from small molecules materials. Compared with fitted analytical potential energy surfaces, direct more user-friendly in that it obtains all needed energies, gradients, and couplings (NACs) by structure calculations. However, the NAC usually does not conserve angular momentum or center of mass widely mixed quantum-classical algorithms, particular, trajectory surface hopping, semiclassical Ehrenfest,...

Machine-learned representations of potential energy surfaces generated in the output layer a feedforward neural network are becoming increasingly popular. One difficulty with is that it often unreliable regions where training data missing or sparse. Human-designed potentials build proper extrapolation behavior by choice functional form. Because machine learning very efficient, desirable to learn how add human intelligence machine-learned convenient way. example well-understood feature...

Dynamics simulations of high-energy O2-O collisions play an important role in simulating thermal energy content and heat flux flows around hypersonic vehicles. To carry out such dynamics efficiently requires accurate global potential surfaces (in most algorithms) state couplings for many energetically accessible electronic states. The ability to treat involving coupled states has been a challenge decades. Very recently, new diabatization method, the parametrically managed by deep neural...

Fitting coupled potential energy surfaces is a critical step in simulating electronically nonadiabatic chemical reactions and transfer processes. Analytic representation of enables one to perform detailed dynamics calculations. Traditionally, fitting performed diabatic avoid the cuspidal ridges adiabatic at conical intersection seams. In this work, we provide an alternative approach by carrying out using modified version Frobenius companion matrices, whose usage was first proposed Opalka...

Cyclin Dependent Kinases (CDKs) are important regulators of cell cycle and gene expression. Since an up-todate review about the pharmacological inhibitors CDK family (CDK1-10) is not available; therefore in present paper we briefly summarize most relevant point out low number selective inhibitors. Among CDKs, CDK9 a validated pathological target HIV infection, inflammation cardiac hypertrophy; however still available. We inhibitor based on 4-phenylamino-6- phenylpyrimidine nucleus. show...

We present quasiclassical trajectory simulations of the high-energy collision-induced O((3)P) + N2 reaction. The simulation results show that reactive scattering may proceed on both (3)A' and (3)A″ potential energy surfaces, but reaction surface overwhelmingly dominates. At total energies collision slightly above threshold, NO(X(2)Π) product is found to be scattered primarily in forward direction, at higher energies, fraction NO products scatter backward direction increases. Two-dimensional...

Faced with the contradictory results of two recent experimental studies [Jara-Toro et al., Angew. Chem. Int. Ed. 2017, 56, 2166 and Chao 2019, 58, 5013] possible catalytic effect water vapor on CH3 OH + reaction, we report calculations that corroborate conclusion made by al. extend rate constant evaluation down to 200 K. The constants reaction catalyzed a molecule are computed as functions temperature relative humidity using high-level electronic structure kinetics calculations....