Structure and stability of small lithium-chloride Li_nCl_m^(0,1+) (n ≥ m, n = 1–6, m = 1–3) clusters

Abstract

In the present study, we report the results of a detailed theoretical investigation along with the experimental observations of chlorine-doped small lithium clusters. The cluster ions of the type LiCl (n ≥ m, n = 1-6, m = 1-3) were obtained by the evaporation of LiCl from a Knudsen cell as a chemical reactor in the temperature range between 1800 and 2700 K. Heterogeneous clusters with more than one Cl atom are produced and detected for the first time, and the experimental conditions for formation and stability are examined. The structural characteristics and stabilities of neutral and positively charged LiCl species are analyzed by using quantum chemistry methods. Doping lithium clusters with chlorine increases their stability, although there is a typical closed-shell-open-shell alternation in stability. Calculated dissociation energies are the best indicator of cluster stability of experimentally detected clusters. Heterogeneous lithium-chloride clusters can be viewed as species consisting of m negative Cl ions and a positively charged Li "cage"; upon ionization, an electron departs from the lithium cage. An important reason for the higher stability of closed-shell clusters is the delocalization of electrons over the lithium cage, which is more energetically favored than localization of electrons between two lithium atoms. According to their ionization energies, the titled clusters can be classified as "superalkalis".

Theoretical and experimental investigation of geometry and stability of small potassium‐iodide KnI (n = 2–6) clusters

“…The most stable neutral cluster species up to the n = 5 favor planar structures. We obtained some similar structures to those published for Li n I ( n = 2–6) and Li n Cl ( n = 2–6), however, the potential energy surface seems even shallower, and since we included higher spin structures, more isomers are obtained. The change from planar to the 3D most stable structures takes place at six K atom, as in the case of Li clusters.…”

“…Potassium‐iodide (KI) and its cation (KI + ) are ionic salts. Species K 2 I + , similar to corresponding lithium‐chloride cluster Li 2 Cl + , is recognized as ionic species. Hence, their properties are different from other species discussed here.…”

“…The lowest‐lying isomers of potassium‐iodide K n I ( n = 2–6) clusters were found by using a random‐kick procedure, which represents a variant of the stochastic search method, first reported by Saunders, and later modified by Tai and Nguyen . This randomized algorithm was already used for obtaining the lowest isomers of heterogeneous lithium clusters, Li n I ( n = 2–6) and Li n Cl m ( n > m, n = 1–6, m = 1–3). It consists of two parts.…”

LinI (n=2-8) ve Lin (n=2-9) Topakların Doğrusal Olmayan Optik Aktivitelerinin Kuramsal Olarak İncelenmesi

“…Son on yılda, LinX (n > 1 ve X = Cl, Br, F veya I) tek halojen atom katkılı lityum topakları elektrokatalizler, soğutma sistemleri, lityum bazlı piller, süper tuzlar, lineer olmayan optik sensörler, yüksek basınçlı elektrikler, kurutucular, nanotüpler, iletişim ve veri depolama sistemlerinde uygulama olasılıkları sebebiyle deneysel ve teoriksel topak çalışan bilim adamlarının araştırma konuları olmuştur. [1][2][3][4][5][6][7][8][9][10]. Saf lityum topaklarına dışarıdan saf bir katkı ilave edilmesiyle oluşan bu yeni topakların moleküler yapı parametrelerinde, kararlılıklarında, enerjiktelerinde, elektronik özelliklerinde, polarizasyonlarında ve bağlanma doğalarında temel değişikliklere yol açabileceği iyice bilinmektedir.…”

“…Saf lityum topaklarına dışarıdan saf bir katkı ilave edilmesiyle oluşan bu yeni topakların moleküler yapı parametrelerinde, kararlılıklarında, enerjiktelerinde, elektronik özelliklerinde, polarizasyonlarında ve bağlanma doğalarında temel değişikliklere yol açabileceği iyice bilinmektedir. LinCl [2,5], LinBr [3,11], LinF [4,8,12,13] ve LinI [9,14,15] topaklarında kullanılan halojen atomları genellikle saf olarak katkılanmış tek atomlardır. Bu tür topaklar hipervalent (hipermetalasyonlu veya hiperlitikseli) topaklar olarak da adlandırılır.…”