Environ v3.1

New in version 3.1:

• fix memory bug in soft-sphere interface, crashing for large systems
• improved interface (getters) for coupling with FHI-aims
• add possibility to use Environ with grand canonical (constant potential) simulations from QE 7.2
• simplified configure and installation

Problems fixed in version 3.1:

• fix bug in coupling lgcscf with Environ
• fix bug in double-cell mapping

Incompatible changes in version 3.1:

v3.0

New in version 3.0:

• new ms-gcs functionality
• new field-aware ionic boundary feature
• new Environ API for use by host programs (see Environ read-the-docs for API documentation)
• new stand-alone programs (running Environ from cube file, computing Environ descriptors)
• support for negative surface tension
• added optional volume/surface output
• further decoupling from QE (new install procedures)
• FFTXlib and UtilXlib updated to QE 7.0
• improved performance of ionic boundary calculations
• improved feature-dependent citations
• updated testcode to Python3

Problems fixed in version 3.0:

• restored QE XSpectra support

Incompatible changes in version 3.0:

• QE decoupling changes no longer support old install procedure

Environ v2.0.3

Problems fixed in version 2.0.3:

• fixed bug in NEB and added an NEB test with dielectric
• loosened the tolerance for difference between expected and integrated electronic charge

Environ v2.0.2

Problems fixed in version 2.0.2:

• restored NEB support

Environ v2.0.1

Problems fixed in version 2.0.1:

• missing lowmem derivatives case for ionic solvent-aware interfaces

Environ v2.0

New in version 2.0:

• double-cell functionality
• semiconductor embedding functionality (thanks to Dr. Quinn Campbell)
• F2003 OOP standards applied throughout the code
• uniform formatting
• calculation of the g-vectors was made internal to Environ,
  as well as the initialization of the dfftp variable type for
  the system and environment cells
• during input reading, Environ outputs a summary of default settings

Problems fixed in version 2.0:

• CP energies now contain correct de_dboundary terms
• improved compatability with QE >= 6.3

Incompatible changes in version 2.0:

• Environ no longer uses QE's addsonpatch.sh script during installation

Known problems in Environ 2.0 :

• double-cell scaling
• spurious forces with solvent_mode = 'system'

Environ v1.1

Minor update of Environ. The new features with respect to Environ 1.0 are:

• Confining potential as additional embedding environment
• Non-linear models of diffuse layers (full Poisson-Boltzmann and modified PB)
• Analytical 1D models of the diffuse layer (Gouy-Chapman-Stern correction of electrostatic potential)

Some minor bugs have been fixed from the previous version, in particular:

• improved minimum image convention for generation of functions: it solves
  incorrect behavior for non-orthorombic cells
• bugfix: laplacian of erfc was not correctly implemented for 1-D and
  2-D systems (calculations with dielectric and 1- or 2-D system boundary
  were affected)
• fixed a bug in dielectric regions when optical permittivity is different from vacuum
• decreased tolerance for check on electronic charge in utils_charges.f90
• fixed a small bug that prevented compilation in environ_init.f90
• modified the local arrays in compute_convolution_fft to avoid
  large automatic arrays written on the stack (segmentation fault on
  Mac with default compilation options, i.e. small stack)

Environ 1.0

First official release of the Environ library for multiscale environment effects in condensed-matter simulations. Environ 1.0 is coupled with the Quantum Espresso package (www.quantum-espresso.org).
The new features of Environ-1.0 are the following:

• Preconditioned conjugate gradient solvers for the generalized Poisson equation, needed in dielectric embedding environments.
• Extension to solve linearized (possibly size-modified) Poisson-Boltzmann problems, needed in modeling dilute electrolyte embedding environments.
• Non-linear solvent-aware definition of the continuum interface, to avoid artifacts in the definition of the boundary in complex systems, such as unphysical pockets of continuum embedding environments that are smaller than the solvent molecular radius.
• A full set of tests to check consistency of compilation and implementation.

The previous functionalities of Environ, available to all the supported distributions of Quantum Espresso, are the following:

• Continuum dielectric solvation model, defined self-consistently on the electronic density of the system.
• External pressure model, defined in terms of the quantum-volume of the system.
• External surface tension model, defined in terms of the quantum-surface of the system.
• Point-counter-charge correction schemes to remove periodic boundary conditions artifacts in isolated (0D) and slab (2D) systems.
• Modifications of Martyna-Tuckermann PBCs correction schemes to account for the presence of a continuum dielectric embedding.
• Fully tested and easier to use external fixed charge densities of arbitrary shape and dimensionality.
• External user-defined dielectric regions of arbitrary shape and dimensionality, to simulate the effect of complex environment such as interfaces, substrates, nanoparticles, etc.
• Restart, with the possibility to include environment effects from the initialization step, providing a substantial speedup for geometry optimization calculations.

The above functionalities are coupled with the following types of calculations:

• Possibility to perform single point calculations, geometry optimizations, and Born-Oppenheimer molecular dynamics simulations, through the PW code of the Quantum Espresso package.
• Possibility to perform transition state calculations via the nudged elastic band method, through the NEB code of the Quantum Espresso package.
• Possibility to perform the calculation of optical spectra via time-dependent density functional perturbation theory, through the TDDFpT code (only for the continuum dielectric contribution).
• Only starting from QE-5.3.0, Environ-0.2 is coupled with the CP code of the Quantum Espresso package, to perform Car-Parrinello and damped molecular dynamics simulations.

All the above simulations are compatible with the main features of Quantum Espresso, namely pseudo-potentials-based plane-wave periodic-boundary-conditions simulations at the density functional theory level, with k-point integration. In particular the following features are all compatible with Environ (a more comprehensive list of the capabilities of Quantum Espresso can be found in the project documentation):

• Norm-conserving, ultrasoft and projector-augmented wave (PAW) pseudopotentials.
• Local density approximation (LDA) functionals, Generalized Gradient approximation (GGA) functionals, hybrid functionals, van der Waals (vdW) nonlocal density functionals.
• Hubbard U.