NANOVIBR: Parallel Codes for Semiempirical Quantum Chemical and Harmonic Vibration Large-Scale Calculations PARVAZ K. BERZIGIYAROV, 1 VALENTINE A. ZAYETS, 1 ILYA Y. GINZBURG, 1 VLADIMIR F. RAZUMOV, 1 ELENA F. SHEKA 2 1 Institute of Problems of Chemical Physics, Russian Academy of Sciences, Moscow, Russia 2 People’s Friendship University of Russia, ul. Miklukho-Maklaya 6, Moscow, 117302 Russia Received 7 August 2002; accepted 9 December 2002 DOI 10.1002/qua.10544 ABSTRACT: Package NANOVIBR is a further development of the NANOPACK software (Int J Quantum Chem 2002, 88, 449) and is dedicated to both semiempirical quantum chemical (QCh) calculations of nano-sized systems and harmonic vibrational problem solution for several hundred atom systems, with a particular stress on the latter. Sequential codes CLUSTER-Z1 and CLUSTER-Z2 form the ground of the package and provide extended QCh calculations of structural and electronic characteristics in the sp- and spd-basis, as well as of force fields, harmonic vibrational frequencies, infrared, and Raman spectra intensities. The combination of fine-grained (self-consistent field calculation) and coarse-grained (Hessian and spectra intensities) regimes of the parallel codes implementation results in a considerable enhancement of the calculation speed-up. © 2003 Wiley Periodicals, Inc. Int J Quantum Chem 96: 73–79, 2004 Key words: fine-grained and coarse-grained parallelism; harmonic vibration large- scale calculations; NANOVIBR parallel codes; quantum chemistry; semiempirical NDDO and NDDO-WF approaches; sp- and spd-basis Introduction T he package NANOVIBR is a further develop- ment of the NANOPACK [1] software and is dedicated to both semiempirical quantum chemical (QCh) calculations of nano-sized systems and har- monic vibrational problem solution for large nano- sized systems, with a particular stress on the latter part. Sequential codes CLUSTER-Z1 [2] and CLUS- TER-Z2 [3] form the ground of the NANOVIBR package, providing extended QCh calculations of structural and electronic characteristics of large polyatomic systems in the sp- and spd-basis, as well as of force fields, harmonic vibrational frequencies, infrared (IR), and Raman spectra intensities. The Correspondence to: E. F. Sheka; e-mail: sheka@icp.ac.ru Contract grant sponsor: Russian Foundation for Basic Re- search. Contract grant number: 01-07-900-56. International Journal of Quantum Chemistry, Vol 96, 73–79 (2004) © 2003 Wiley Periodicals, Inc.