Release: September 2021
System requisites:
Considerable efforts have been put into the improvement of the portability of the VB2000 code. VB2000 has been tested in the past on several platforms with different compilers. It is expected that the code can be ported on to many other platforms without major changes.
C and Fortran compilers are required for installing VB2000. The most common ones are gcc / gfortran, Intel (icc, ifort, OneAPI) and Portland (PGI). Please note that, from version 3.0, we have started migrating VB2000 to newer Fortran Standards, so it is not pure Fortran 77 anymore. VB2000 was officially tested using gcc / gfortran versions 5.5, 9.3 and 10.1, and intel oneAPI 2021.3, but older versions were tested in a wider range of compilers and no major problems are expected using other compilers. If you have any problems installing VB2000, please contact us. If you have problems installing the GAMESS / VB2000 version, please contact the GAMESS development team.
Linux platforms: VB2000 was developed under Linux and tested in various Linux distributions.
Windows: VB2000 can be used in Windows currently in to ways. The first is using Cygwin, which is an emulator of Unix-like features for Windows. The second is using the Windows Subsystem for Linux (WSL) which is available from Windows 10.
Mac OS: VB2000 3.0 is supported under Mac OS, in both older versions with Intel processors and newer versions with Apple M1 processors (it was tested with the gcc / gfortran compilers).
Installation Instructions:
For installation instructions, please see the file vb2000.README inside the tarball.
Changelog for version 3.0:
The VB2000 3.0 release was initially intended to be the 2.8 version, but due to significant postponements in the release and the inclusion of new developers in the VB2000 team, we have renamed it as the 3.0 version for the public release in October 2021. VB2000 3.0 was also released together with the GAMESS 2021 R2 (September 30th) release. If you want to use the GAMESS / VB2000 version, please check it out in the GAMESS home page.
This version is primarily due to developments that removes restrictions on the kind of GAMESS calculation that is used to construct initial guess orbitals in GAMESS / VB2000. Now all values of SCFTYP can be used, allowing UHF, GVB and MCSCF orbitals, in addition to RHF and ROHF. All kinds of DFT orbitals can be used. MP2, coupled-cluster and configuration interaction can be calculated but the HF orbitals are used. GVB is restricted to closed shell and uses the actual “bond” GVB orbitals after using localized orbitals to calculate the GVB CI pairs. The GVB orbitals can be a particularly good initial guess to use VB2000 for more advanced VB methods than GVB-PP. RUNTYP = OPTIMIZE and RUNTYP = HESSIAN can now be used to optimize the geometry or calculate frequencies with the GAMESS method before doing a VB2000 calculation, as well as optimizing the geometry or calculate frequencies with the VB method. RUNTYP =IRC and RUNTYP = SURFACE can be used with a range of GAMESS methods, calculating VB function at each point. $GMSPATH/vb2000/DOC/GMS_VB_test.README explains these methods in more detail and describes a set of test files for them. See also the files ChangeLog and Change_VB2.7-3.0.md in the DOC directory for more details and for other developments.
Other new features are:
In order to download VB2000, you need to register. Please fill the form below. You will receive a copy of the VB2000 source code soon.
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