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Q-Chem 是分子的結構、 活性，準確地預測綜合 ab
從頭算量子化學包和振動、 電子和核磁共振光譜。新的發行版本的 Q-Chem 4.0
表示方法論的先進最高性能的 DFT/高頻計算從高級別職位 HF 關聯方法： |
Q-Chem is a comprehensive ab initio quantum
chemistry package for accurate predictions of
molecular structures, reactivities, and vibrational,
electronic and NMR spectra. The new release of Q-Chem
4.0 represents the state-of-the-art of methodology
from the highest performance DFT/HF calculations to
high level post-HF correlation methods:
Dispersion-corrected and double hybrid DFT
functionals;
Faster algorithms for DFT, HF and coupled-cluster
calculations;
Structures and vibrations of excited states with TD-DFT;
Methods for mapping complicated potential energy
surfaces;
Efficient valence space models for strong
correlation;
More choices for excited states, solvation and
charge-transfer;
Effective Fragment Potential and QM/MM for large
systems;
Shared-memory for multicores and implementations for
GPU's.
Property Analysis
Automated Geometry and
Transition Structure Optimization
●
Uses Dr. Jon
Baker's OPTIMIZE package
○
Utilizes redundant internal coordinates to ensure
rapid convergence
even without an initial force
constant matrix
●
Geometry
Optimization with General Constraints
○ Can
impose bond angle, dihedral angle (torsion) or
out-of-plane
bend constraints Freezes atoms in Cartesian
coordinates
○
Desired constraints do not need to be imposed in
starting structure
●
Optimizes in
Cartesian, Z-Matrix or delocalized internal
coordinates
●
Eigenvector Following (EF) algorithm for minima and
transition states
●
GDIIS algorithm for minima
○
Greatly speeds up convergence to an equilibrium
geometry
●
Intrinsic Reaction Coordinates (IRC) following
○
Connect equilibrium geometries and transistion
states along
reaction paths.
○
Ab initio dynamics with extrapolated z-vector
techniques for MP2
and/or dual-basis methods
○
Improved robustness with Version 4.0
●
Freezing and Growing String Methods for efficient
automatic reaction path finding
