Calculation

• IR and Raman spectra and its vibrational mode are calculated by Firefly QC package [1], which is partially based on the GAMESS (US) [2] source code.
• The B3LYP functional with 6-311+G(d,p) basis set is used.
• Horizontal axis of the spectra are corrected by wavenumber-linear scaling (WLS) [3]. The scaling falctor of WLS is s_WLS = α - 10^-5 β ν.
• Parameters of the compound are refferd to PubChem [4].

Reference

[1] Alex A. Granovsky, Firefly version 8, www http://classic.chem.msu.su/gran/firefly/index.html
[2] M.W.Schmidt, K.K.Baldridge, J.A.Boatz, S.T.Elbert, M.S.Gordon, J.H.Jensen, S.Koseki, N.Matsunaga, K.A.Nguyen, S.Su, T.L.Windus, M.Dupuis, J.A.Montgomery J.Comput.Chem. 14, 1347-1363 (1993)
[3] H.Yoshida, K.Takeda, J.Okayama, A.Ehara and H.Matsuura, J. Phys. Chem. A 106, 3580 (2002)
[4] National Center for Biotechnology Information. PubChem Compound Summary for CID 1023, Pyrophosphoric acid. https://pubchem.ncbi.nlm.nih.gov/compound/Pyrophosphoric acid. Accessed Jun. 18, 2022.