High Throughput Quantum Chemistry

Advances in the stability and efficiency of electronic structure codes along with the increased performance of commodity computing resources has enabled the automated high-throughput quantum chemical analysis of materials structure libraries containing thousands of structures. This allows the computational screening of a materials design space to identify lead systems, estimate critical structure-property limits and optimize the reaction process. High throughput quantum chemistry has been proven an invaluable tool in informing experimental discovery and development efforts. Challenge of chemical process calculation is tackled by allowing computations via a direct application programming interface and by encouraging machine-readable input and output.

Figure 1. A schematic overview of the data-driven approach to predict experimental pK_a of TM hydride complexes. (Kobayashi, M.; et al. 2020)

Advantages

• Calculations can be run with very simple text files.
• Facilitate post-processing and complex workflows.
• Facilitate interoperability with top-level computation driver.
• Well suited to distributed computation of large numbers of independent tasks.

Our Services

At Alfa Chemistry, we have established a high-throughput platform based on quantum mechanics providing implementations of density-fitted (DF), density functional theory (DFT) calculation, Hartree-Fock, many-body perturbation theory, configuration interaction, density cumulant theory, symmetry-adapted perturbation theory (SAPT), and coupled-cluster (CC) theory through perturbative triples [CCSD(T)]. Our fast and high-quality services include the following:

• Hartree-Fock and Kohn-Sham DFT

DF algorithms are particularly efficient, and we use it to perform computations on hundreds of atoms. The Energies and gradients are available for restricted and unrestricted Hartree-Fock and Kohn-Sham (RHF, RKS, UHF, UKS), and restricted open-shell Hartree-Fock (ROHF). Moreover, almost all commonly used functionals are available due to the interface with various library.

• Perturbation theory

At Alfa Chemistry, we feature Møller-Plesset perturbation theory up to the fourth order, which means the full configuration interaction code can be applied to generate arbitrary-order MPn and Z-averaged perturbation theory (ZAPTn) results for very small molecules. Our experts can also compute the electron affinities and ionization potentials utilizing second-order electron-propagator theory (EP2) and the extended Koopmans’s theorem (EKT).

• Coupled-cluster theory

Our high throughput quantum chemistry platform supports conventional CC energies up to singles and doubles (CCSD) plus perturbative triples CCSD(T). We also support the approximations based on frozen natural orbitals (FNOs) which can reduce the computational cost of CC computations. In addition, our scientists can apply it in the equation-of-motion CCSD, the CC2 and CC3 approximations, linear-response properties such as optical rotation.

• Orbital-optimized correlation methods

Alfa Chemistry provides a range of orbital-optimized methods including MP2, MP3, MP2.5 and linearized coupled-cluster doubles (LCCD). We select orbitals that can minimize the energy of the targeted post-HF wavefunction. DF energies and analytic gradients are available for all of these methods.

• Symmetry-adapted perturbation theory

We compute intermolecular interaction energies and leverages efficient with popular DF algorithms and wavefunction-based SAPT. Our groups have ability in computing the zeroth-order SAPT (SAPT0) interaction energies between open-shell molecules with either UHF or ROHF reference wavefunctions. We can quantify the interaction between fragments of the same molecule by using the obtained intramolecular formulation of SAPT0.

• Configuration interaction

Configuration interaction singles and doubles (CISD), quadratic CISD (QCISD), and QCISD with perturbative triples [QCISD(T)] for RHF references are available. We also provide an implementation of full configuration interaction (FCI) and the restricted active space configuration interaction (RASCI) approach.

• Multi-reference methods

We can perform multireference CC calculations through an interface where high-order excitations as well as perturbative methods are supported.

• Density cumulant theory

Our high throughput quantum chemistry platform uses the cumulant of the two-electron reduced density matrix (RDM) instead of a many-electron wavefunction.

• Relativistic corrections

We can perform electronic structure computations with scalar relativistic corrections either by using fourth-order Douglas–Kroll–Hess (DKH) or the exact-two-component approach to supplement the one-electron Hamiltonian of a nonrelativistic theory for relativistic effects.

• Composite and many-body computations

Our simple and powerful user interface can carry out automate multi-component computations, including focal-point approximations, complete basis-set (CBS) extrapolation, basis-set superposition corrections [counterpoise (CP), no-counterpoise (noCP), and Valiron–Mayerfunctional counterpoise (VMFC)], and many-body expansion (MBE) treatments of molecular clusters.

Why Choose Us?

• Our build system, driver, and distribution system have been developed specifically to conduct high throughput quantum chemistry.
• We can perform calculations routinely undertaken in bulk for use in various data analysis pipelines.
• Our high throughput quantum chemistry have advantages of simpler analytic gradient expressions and improved accuracy.

High throughput quantum chemistry provides an effective way to optimize the chemical process. Our high throughput quantum chemistry services remarkably reduce the cost, promote further experiments, and enhance the understanding of chemical process for customers worldwide. Our personalized and all-around services will satisfy your innovative study demands. If you are interested in our services, please don't hesitate to contact us. We are glad to cooperate with you and witness your success!

Reference

• Sinha, V.; et al. Accurate and rapid prediction of pKa of transition metal complexes: semiempirical quantum chemistry with a data-augmented approach. Physical Chemistry Chemical Physics. 2021, 23: 2557-2657.