The Raman spectrum of isolated water clusters

Abstract

Cold water oligomers (H 2 O) n and (D 2 O) n with n = 2-5 are assigned in spontaneous Raman scattering spectra of seeded rare gas expansions for the first time. Comparison with infrared spectra provides direct experimental insights into the hydrogen bond-mediated excitonic OH oscillator coupling, which is responsible for ultrafast energy transfer between water molecules, usually suppressed by isotopic dilution in femtosecond experiments for the condensed phase. The experimental coupling constants are compared to those in state-of-the-art full-dimensional water potential energy hypersurfaces, leaving room for improvement in the description of the coupled dynamics in water. Evidence for intensified Fermi resonance between OH stretching and OH bending motion beyond water trimers is collected.

An accurate and efficient computational protocol for obtaining the complete basis set limits of the binding energies of water clusters at the MP2 and CCSD(T) levels of theory: Application to (H2O)m, m = 2-6, 8, 11, 16, and 17

“…Small water cluster configurations (both at their minima and other parts of the corresponding potential energy surfaces) have been successfully used [3][4][5][6][7][8][9][10][11][12][13][14] in the parametrization of interaction potentials to simulate the properties of liquid water and ice. Although structural and spectroscopic information of medium size water clusters has been reported experimentally, [15][16][17][18][19][20][21][22][23][24][25][26][27][28] measurements of their binding energies are scarce, limited to date only for the water dimer 29 and trimer, 30 using a combined experimental-theoretical approach. The energetics of hydrogen bonds in water clusters are important not only for the development of interaction potentials for water but also since they serve as benchmarks for assessing the accuracy of theoretical approaches aiming at developing more costa) Author to whom correspondence should be addressed.…”

“…In 2004, we reported single point MP2/aug-cc-pVQZ energies for the various isomers 41,42 of (H 2 O) 20 and CCSD(T)/aug-cc-pVTZ energies for the two isomers 43 of (H 2 O) 8 . In 2009, the CCSD(T)/aug-cc-pVTZ calculations were extended 44 to the cage tetrakaidecahedron (H 2 O) 24 cluster-one of the building blocks of the structure I (sI) hydrate lattice-using all 223 200 processors of Oak Ridge National Laboratory's "Jaguar" supercomputer (ranked #1 on the top 500 list at the time), demonstrating a sustained performance of 1.39 PetaFLOP/s (1.39 × 10 15 floating point operations per second) in double precision.…”

“…80 In our ongoing effort to study the water cluster structures and energetics, 4,41,43,61,71,75,80 we currently report on a computational protocol that can be used to obtain accurate binding energies (at the MP2/CBS and CCSD(T)/CBS levels of theory) for water clusters. We validate this protocol with full calculations for clusters up to the water octamer and use it to predict the binding energies for the (H 2 O) 16 , (H 2 O) 20 , and (H 2 O) 24 clusters. The validation relies on state-of-the-art techniques approaching their complete correlation and basis set limits.…”

Water Supersolid Skin

“…Water molecular undercoordination stiffens the stiffer ω H significantly [49,50]. The ω H has a peak centered at 3200 cm −1 for bulk water, and at 3450 cm −1 for the skins of both water and ice (see Fig.…”

Исследование Индукционно-Резонансного Взаимодействия Кластеров Воды В Минералах Фторапатита Методами Поляризационной ИК И Кр-Спектроскопии

“…полос в рамках кластерной схемы строения воды (Н 2 О) n в соответствии с литературными данными [33,34]. Особенность спектров КР в диапазоне 4000−3000 сm −1 заключалась в значительном различии интенсивностей (I) полос для компонент излучения, рассеянного в ортогональных направлениях (I z z и I z y ) и (I y y и I y z ) соответственно вдоль и поперек c-каналов об-разца (рис.…”