chemps2 command not found

Introduction

When you run more command in linux terminal / console, you get the following error message

chemps2: command not found

or when using sudo you get the following error message

sudo: chemps2: command not found

Solutions to chemps2: command not found

How To Fix chemps2: command not found in Ubuntu / Debian / Kali Linux / Raspbian

In Ubuntu chemps2 is provided by chemps2 package.

chemps2 is:

chemps2 is a scientific library which contains a spin-adapted implementation of the density matrix renormalization group (DMRG) for ab initio quantum chemistry. This wavefunction method allows one to obtain numerical accuracy in active spaces beyond the capabilities of full configuration interaction (FCI), and allows one to extract the 2-, 3-, and 4-particle reduced density matrices (2-, 3- and 4-RDM) of the active space.

For general active spaces up to 40 electrons in 40 orbitals can be handled with DMRG, and for one-dimensional active spaces up to 100 electrons in 100 orbitals. The 2-RDM of these active spaces can also be easily extracted, while the 3- and 4-RDM are limited to about 28 orbitals.

When the active space size becomes prohibitively expensive for FCI, DMRG can be used to replace the FCI solver in the complete active space self consistent field (CASSCF) method and the corresponding complete active space second order perturbation theory (CASPT2). The corresponding methods are called DMRG-SCF and DMRG-CASPT2, respectively. For DMRG-SCF the active space 2-RDM is required, and for DMRG-CASPT2 the active space 4-RDM.

This package installs the executable which parses Hamiltonians in fcidump format, performs DMRG-SCF and DMRG-CASPT2 calculations as specified by the user.

To fix this problem, we can install more using the command below.

sudo apt-get -y install chemps2

This command might take some time to finish depending on your machine internet connection.

You can also use apt command to install chemps2.

sudo apt -y install chemps2

Or if you have aptitude installed you can use the following command.

sudo aptitude install chemps2

Summary

In this tutorial we learn how to fix chemps2 command not found error in Ubuntu / Debian / Kali Linux or Raspbian distribution.