# SCIGRESS - Computational Tools - MO-S (MOS-F)

MO-S version 1.0a is a semiempirical molecular orbital package to calculate spectroscopic properties of a molecule mainly.

#### Main features:

The semiempirical molecular orbital methods MNDO, AM1, PM3, PM5, RM1, PDDG/MNDO, PDDG/PM3, ZINDO/S, CNDO/S, CNDO/S2, CNDO/S3, and CNDO/2 are available.

Self-consistent field calculations using restricted Hartree-Fock (RHF), unrestricted Hartree-Fock (UHF), and restricted open-shell Hartree-Fock (ROHF) wavefunctions are available.

Geometry optimization using Cartesian, internal, and delocalized internal coordinates is available for RHF, UHF, and ROHF wavefunctions with the MNDO, AM1, PM3, PM5, RM1, PDDG/MNDO, and PDDG/PM3 model Hamiltonians.

Spectroscopic calculations with configuration interaction singles (CIS).

Spectroscopic calculations with random phase approximation (RPA).

Electron density and dipole moment in excited states available from CIS wave function.

Spectroscopic calculations of an open-shell system with Restricted Open-shell Hartree-Fock/CIS method (ROCIS method).

Frequency-dependent polarizability, α.

First hyperpolarizability β for Static, Electro-optic Pockels effect, Second harmonic generation and Optical-rectification β.

Second hyperpolarizability γ for Static, DC-electric field induced Kerr effect, DC-electric field induced second harmonics, Third harmonic generation, Degenerate four-wave mixing and DC-electric field induced optical rectification.

Prediction of the following molecular properties in the presence of a solvent using the SCRF calculation by means of the Onsager model:

Electronic spectrum using the CIS/RPA wave function.

Electron density and dipole moment in excited states using the CIS wave function.

Frequency-dependent polarizability, α, first hyperpolarizability, β, and second hyperpolarizability, γ, using the CIS wave function.

Analytic, Pariser-Parr, Nishimoto-Mataga, Nishimoto-Mataga-Weiss, Ohno, Ohno-Klopman, and DasGupta-Huzinaga formulas for evaluation of the two-center electron repulsion integrals are available for ZINDO/S, CNDO/S, CNDO/S2, and CNDO/S3.

DIIS (direct inversion in the iterative subspace) and level-shift method for improving the SCF convergence.

Rational function optimization (RFO) and Geometry DIIS (GDIIS) method for improving the convergence of geometry optimization.

Approximate Hessian (with respect to delocalized internal coordinates) for improving the convergence of geometry optimization.

Automatic calculation of the cavity radius for a solute.

Automatic input system of dielectric constant and refractive index by specifying a solvent name.

Rotational constants and angles between principal axes of inertia and dipole/transition moments.

Coordinate input format from the Gaussian Symbolic Z-matrix and the MOPAC Internal Coordinates.