Molden is a commonly used computational software by Gijs Schaftenaar, useful for analyzing the output of many ab initio packages, such as Gaussian, Dalton, Molcas, ADF, and several others. Thanks to Molden even undergraduate students can, for example, investigate the shapes of molecular orbitals or examine calculated vibrational spectra.

In most cases, nowadays Molden is installed on computer running Intel-based computers, with OS such as Windows, MacOS, or – most commonly – Linux in one of its many flavors.

Can Molden be installed on an old computer featuring a PPC processor?

In the following, a step-by-step procedure to install Molden 6.2 (the latest version at the moment) on a PPC computer will be shown.

The computer is “mirrored drive door” PowerMac with a G4 7455 PPC processor running at 1.25 MHz, including the AltiVec “Velocity Engine” vector processor, equipped with 2GB of RAM (the maximum amount for this machine).

In order to be able to compile Molden 6.2, the Ubuntu 12.04 LTS Linux OS was installed on the test machine along with other OSs (OS X 10.5 Lion, OS X 10.4 Tiger, MorphOS, and MacOS 9.2). When booting, the OS can be chosen by keeping the Option key pressed.

Now, open a Terminal window and type:

sudo apt-get install build-essential wget libxmu-dev

sudo apt-get install libX11-6 libX11-dev libgl1-mesa-dev

sudo apt-get install libglu1-mesa-dev xutils-dev gfortran

You will be asked for the administrator password. Now update your system by typing:

 sudo apt-get update; sudo apt-get upgrade

When prompted press “Y” on your keyboard (“S” in the Italian version of the OS). Now your system is ready for installing Molden. First you need to get the source of the software by typing:

 wget ftp://ftp.cmbi.ru.nl/pub/molgraph/molden/molden6.2.tar.gz

Extract the compressed file by typing:

tar xvfz molden6.2.tar.gz

rm molden6.2.tar.gz

cd molden6.2

Now, you will find yourself in the “molden6.2” directory.

 make

If everything is ok, you can now delete the useless files:

rm *.o *.f *.c *.f.g77 *.for *.old make_vms.com makefile* tt

mv surf surf_dir; cp surf_dir/surf .; rm –rf surf_dir

mv ambfor ambfor_dir; cp ambfor_dir/am* .; rm -rf ambfor_dir/

You can come back to the parent directory by typing:

 cd ..

Now your $HOME/molden6.2 directory contains all the executable. If you use the tcsh, you may want to simplify the access of the program by adding the following lines to your .cshrc file (located in your $HOME directory).

 # Molden

set path = ( $path $HOME/molden6.2)

That’s it. Molden is ready to use! Just type “molden” or “gmolden” (OpenGL version) to enjoy it.