Our multilingual customer support team is ready to help you - 24h hours a day from Monday to Friday. Fast & highly qualified support. Over the years, this broker has gained the reputation among the most reliable trading platforms. This user guide focuses on the semiempirical quantum mechanical methods GFNn-xTB, their descendants, and corresponding composite schemes as implemented in the xtb (extended tight binding) program package. (IFSC License No.: 000302/185). Please read our contributing guidelines before contributing to this project Contributors. XTB is registered in Belize under Registered Number 153,939 Company address: 35 Barrack Road, 3rd Floor, Belize City, Belize, C.A. User Guide to Semiempirical Tight Binding¶. We are developing this program to make our research possible. XTB is the brand name for the XTB Group, which includes X-Trade Brokers DM SA, XTB Limited, and XTB Sucursal. The forex broker has over ten offices across the cara belajar iq option world xtb and offers services in over ten languages to include English, Spanish, Polish, Czech, French, Hungarian, Italian, Russian. You can contact us by phone, e-mail or online chat XTB’s performance of activities may require a transfer of personal data to entities which are performing services for and on behalf of XTB in other countries, including countries que prefieres forex opciones binarias outside of European Economic Area. XTB is a renowned CFD brokerage company founded in 2002.