The negatively charged nitrogen vacancy centre in diamond is a promising candidate for future nanoscale quantum applications. For its operation it is important to have control of the centres charge state, and to avoid temporary disappearance of the NV-center’s functionality, termed photo-blinking. In this work, we use density functional theory simulations to investigate excitations that result in loss of an electron from NV⁻ to a nearby nitrogen donor (donor-N⁺), leading to NV⁰ and donor-N⁰ charge state, and the corresponding deexcitation. Since these processes involve two different localized defect centres in the diamond lattice (the NV-center and the donor-N) they are non-local excitations. We have studied the de-charging both as a one-photon process and through a sequential two-photon process via the NV-center excited state. We propose de-charging directly from the NV-center to the donor-N as a possible mechanism for photo-blinking of the NV-center that involve an additional electron spin resonance active defect, the donor-N⁰. We have found that the excitation energies are converged when the distance between the two is larger than 10.4 . We also compute excitations to the conduction band edge from NV⁻ (to NV⁰) and from donor-N⁰ (to donor-N⁺) using G₀W₀ + BSE.

金刚石中带负电荷的氮空位中心是未来纳米级量子应用的有希望的候选者。对于其操作，重要的是要控制中心的充电状态，并避免NV中心功能的暂时消失（称为光闪烁）。在这项工作中，我们使用密度泛函理论模拟来调查导致从NV的电子的损失激发^-到附近的氮供体（供体-N ⁺），导致NV ⁰和施主-N ⁰充电状态，以及相应的去激励。由于这些过程涉及钻石晶格中的两个不同的局部缺陷中心（NV中心和施主-N），因此它们是非局部激发。我们已经研究了通过单光子过程以及通过NV中心激发态通过连续两光子过程进行的放电。我们建议直接从NV中心向施主N放电，这是NV中心光闪烁的一种可能机制，其中涉及额外的电子自旋共振活性缺陷施主N ⁰。我们发现，当两者之间的距离大于10.4时，激发能就会收敛。我们还计算激励从NV导带边缘^- （至NV ⁰），并从供体-N ⁰（供体-N ⁺）使用G ₀ W ₀ + BSE。