This record contains the data supporting our recent findings on electron-phonon coupling during photoinduced phase transition. We measure mode- and band-selective electron-phonon couplings during the photoinduced insulator-to-metal phase transition in Ta2NiSe5 (TNS) by frequency-domain angle-resolved photoemission spectroscopy (FDARPES). FDARPES gives us rich information about which band more couples which phonon mode by seeing frequency components of time-resolved angle-resolved photoemission spectra. The experiments indicate 2 THz and 3 THz phonon modes associated with the metallic and semiconducting phases. To get a more atomistic picture of the oscillation, we perform phonon-mode calculations relying on the density-functional theory (DFT).

The computational scheme itself is very standard that density-functional-perturbation theory (DFPT) with semilocal or local exchange-correlation functionals. However, the required computational resources were rather huge, 25,000 core-hour, for a single DFPT with atomic position optimization having 0.1 eV/nm force accuracy for more satisfactory computational parameters. Therefore, the data must be worth as a benchmark within DFT-level calculation for TNS.