These experimental results are corroborated by first principles simulations. In contrast, the oxygen-free photoreaction activates previously inaccessible para configurations through a triplet-state mechanism. Specifically, photoexcited aromatics react with SWCNT sidewalls to undergo a singlet-state pathway in the presence of dissolved oxygen, leading to ortho binding configurations of the aryl group on the nanotube. Here, we explore recently reported photosynthetic protocol and find that it can control chemical binding configurations of quantum defects, which are often referred to as organic color centers, through the spin multiplicity of photoexcited intermediates. However, the chemistry of binding with atomic precision at the single-bond level and tunable control over the binding configurations are yet to be achieved. Applications such as room-temperature single-photon emission and high-contrast bio-imaging have been advanced through aryl-functionalized SWCNTs, in which the binding configurations of the aryl group define the energies of the emitting states. At this time,Īre next three lowest configurations and they are written in (low energy -> high energy) order.Incorporating fluorescent quantum defects in the sidewalls of semiconducting single-wall carbon nanotubes (SWCNTs) through chemical reaction is an emerging route to predictably modify nanotube electronic structures and develop advanced photonic functionality. ![]() Well, if you are not familiar with the very structure of atomic Hamiltonian, we can just concentrate on the energy difference between atomic orbitals and spin-spin interaction. $2s^12p_i^12p_j^12p_k^1$ (since $2s$ and $2p$ have different energy with more than one electron)Īre next three lowest configurations and unfortunately we cannot determine the order of them here. $2s^22p_i^12p_j^1$ (two $p$ electrons have opposite spin) Since 3 $p$ orbitals are equivalent and generally change of interaction between total momentum and atomic environment is smaller than change of kinetic energy/repulsion potential of electrons, by changing states of electrons, If you and your group want to study the structure of atomic Hamiltonian strictly, any other configurations that deviate from Hund's-ground-state will be next excited states, since they produce more powerful momenta-quantum mechanical factors interaction that you cannot figure out yet. You might be confused if you try to understand this using $\sum m$ and $\sum s$ merely, so don't be worry about how to explain the interaction numerically at this time. Here spin-orbit interaction is the one of main ideas of the interaction between total angular momentum and other factors. Atomic Hamiltonian has several terms kinetic energy of electrons + repulsion between electrons + attraction between electrons and protons + (spin-orbit interaction) + (etc). Why? That's the way to lower the interaction between total momentum and any other factors. ![]() If we go further, $2s^22p_i^12p_j^1$ where $i,j=x,y,z$ and both spins need to be same. Hund's rule can tell us what the lowest electron configuration is and firstly originated from the way to choose a state of lowest interaction between total momentum and entire atomic environment within given electron configuration.īy Hund's rule, lowest electron configuration of carbon atom is $2s^22p^2$. Here you seem to have an idea dealing with angular and spin momenta. The first excited state of carbon $C^*$, and the one that explains the existence of $C(+4)$ chemical compounds, is $2s^12p_x^12p_y^12p_z^1$ where all three lone 2p electrons have the same $m_s$ value.Įlectron configuration means the distribution of electrons in atomic (or molecular) orbitals. $1s^2 2s^2 2p^2$ or with some added detail $1s^22s^22p_x^12p_y^1$ and because $=1s^2$, carbon's electron configuration (ground state) can be written as: Overall we can write the electron configuration of carbon as: ![]() Bearing in mind that to satisfy Hund's Rule the latter two 2p electrons are divided over one $p_x$ and one $p_y$ sub-orbital, each with one electron of the same spin quantum number ($m_s=-\frac$). The first 2 occupy the lowest energy atomic orbital possible, that is 1s, so we have $1s^2$ for the first term.įor the remaining four electrons, the next two lowest available atomic orbitals are 2s and 2p and following the above rules that gives us $2s^2$ and $2p^2$. By 'electron configuration' can be understood the way an atom's electrons are arranged in atomic orbitals, in accordance with Pauli's Exclusion Principle, the Aufbau Principle and Hund's Rule, of the lowest possible total energy (known as the Ground State).įor carbon (Z=6), six electron have to be placed in the correct atomic orbitals.
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