:term:`RESTART <RESTART (CCENERGY)>`
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      Do restart the coupled-cluster iterations from old :math:`t_1` and :math:`t_2` amplitudes? For geometry optimizations, Brueckner calculations, etc. the iterative solution of the CC amplitude equations may benefit considerably by reusing old vectors as initial guesses. Assuming that the MO phases remain the same between updates, the CC codes will, by default, re-use old vectors, unless the user sets RESTART = false.

      * **Type**: :ref:`boolean <op_c_boolean>`
      * **Default**: true