Q-Chem 4.3 Release Download

Last update 03/23/2016 (version 4.3.2)


Click here for Q-Chem 4.3 Manual (pdf file)

Click here for Q-Chem 4.3 release log

Click here for Q-Chem 4.3 installation guide

View and download our standard form license agreement here.


Q-Chem 4.3 Package Installation

There are two ways to install Q-Chem 4.3: using universal online installer (recommended) or downloading the complete package for offline installation.

1. Download the universal installer (recommended) for online installation.

wget -N http://www.q-chem.com/download/qcinstall/qcinstall.sh

On Mac OSX if wget is not available on your system please use curl command below:
curl http://www.q-chem.com/download/qcinstall/qcinstall.sh > qcinstall.sh

chmod +x qcinstall.sh

2. Alternatively, download the standard distribution for offline installation by selecting a package below and untar it.

tar xvf qc43.tar

To install please run the installer qcinstall.sh and follow the onscreen instruction. A detailed installation guide and step-by-step tutorials are also provided to guide you through the installation process.


After a successful installation you need to wait to receive the license file by email, and save it as


Q-Chem Package Update and Maintenance

a) to update the installed Q-Chem to the latest distribution, run


You may need to run qcupdate.sh twice, as the first time it may update the installer script.

[Online package maintenance utility qcupdate.sh is the new added feature in 4.2 release. To upgrade pre-4.2 Q-Chem installation please download and run standard installer qcinstall.sh. ]

b) to re-generate and sumit license data, run

$QC/qcinstall.sh --update-lic

c) to receive regular Updates you can use Linux cron utility and add the line below as the cron command. Please consult your system administrator for questions about using cron.

$QC/qcupdate.sh > $QC/qcupdate.log

Q-Chem 4.3 Package Distribution

1. Please select the Q-Chem executable binary codes you wish to download:

Linux 64 Bit Parallel Code based on MPICH (recommended)

Linux 64 Bit Serial/multicore-parallel Code

Linux 64 Bit Parallel Code based on MPICH2 (require MPICH2 being pre-installed)

Windows 32 Bit Parallel Code (Console program, compatible with 64-bit Windows machines)

Windows 32 Bit Serial/multicore-parallel Code (Console program, compatible with 64-bit Windows machines)

Mac Intel OSX 64 Bit Parallel Code (Existing MPICH2 installation is required)

Mac Intel OSX 64 Bit Serial/multicore-parallel Code

2. Please select a download type:

Standard download: for new and upgrade installations

(During installation please be sure to provide us with an accurate e-mail address when prompted for one. It is required so we can locate your account, and contact you should there be any problems with your license request.)

I agree to the terms and conditions in Q-Chem license agreement .

Q-Chem 4 Installation Guide and Step-By-Step Tutorials