I think PyCharm is not a free software, instead you can install PyCharm community following the steps mentioned below.
1. Add PPA running the following command on terminal -
sudo add-apt-repository ppa:mystic-mirage/pycharm
2. After adding PPA, run the following commands one by one on terminal.
sudo apt-get update
sudo apt-get install pycharm-community
If you have purchaed PyCharm, then run sudo apt-get install pycharm instead of sudo apt-get install pycharm-community