Facilitating Minima Search for Large Water Clusters at the MP2 Level via Molecular Tailoring

详细信息    查看全文

• 作者：Jonathan P. Furtado ; Anuja P. Rahalkar ; Sudhanshu Shanker ; Pradipta Bandyopadhyay ; Shridhar R. Gadre
• 刊名：The Journal of Physical Chemistry Letters
• 出版年：2012
• 出版时间：August 16, 2012
• 年：2012
• 卷：3
• 期：16
• 页码：2253-2258
• 全文大小：298K
• 年卷期：v.3,no.16(August 16, 2012)
• ISSN：1948-7185

文摘

Water clusters (H₂O)₂₀ and (H₂O)₂₅ are explored at the M酶ller鈥揚lesset second-order perturbation (MP2) level of theory. Geometry optimization is carried out on favorable structures, initially generated by the temperature basin paving (TBP) method, utilizing the fragment-based molecular tailoring approach (MTA). MTA-based stabilization energies at the complete basis set limit are accurately estimated by grafting the energy correction using a smaller basis set. For prototypical cases, the minima are established via MTA-based vibrational frequency calculations at the MP2/aug-cc-pVDZ level. The potential of MTA in tackling large clusters is further demonstrated by performing geometry optimization at MP2/aug-cc-pVDZ starting with the global minimum of (H₂O)₃₀ reported by Monte Carlo (MC) and molecular dynamics (MD) investigations. The present study brings out the efficacy of MTA in performing computationally expensive ab initio calculations with minimal off-the-shelf hardware without significant loss of accuracy.

Keywords:

large water clusters; molecular tailoring approach; complete basis set limit; Hessian matrix; M酶ller鈭扨lesset second order perturbation (MP2) theory; ab initio methods