[yosyp]

Large-scale Atomic/Molecular Massively Parallel Simulator (LAMMPS) is written in C++ and it's over 20 years old. The FORTRAN codebases seem to be centered around the finite elements/difference methods and the fluid dynamics community.

[sseagull]

Sorry, I wasn't specific. My comment mostly applies to the quantum mechanics (QM) community, rather than molecular dynamics. In QM, many people still run Gaussian/GAMESS/ADF/MolCAS/MolPro/Dalton, which are all Fortran (or majority Fortran). And most are Fortran 90 or earlier.

My background is in QM, so I guess that's my bias showing through :)

[gnufx]

Even in Molecular dynamics, there's dl_poly, for instance. Other things that come to mind in Fortran apart from nwchem are cp2k and castep.

Somewhere under http://www.archer.ac.uk, there's a summary of the time used by various codes on that UK "Tier 1" system.