**System details**

Compound | Iodine dimer |

Formula | I_{2} |

CAS Number | 7553-56-2 |

**Ground state input**

Cubic cell size | 30 a.u. |

PW cutoff (WFS) | 40 Ry |

Pseudopotential(s) | SG15^{[01-03]} () |

## Dielectric Screening

The dielectric matrix of Iodine dimer (I_{2}) is computed in WEST by iterative diagonalization, see Fig. 2 of Ref. [04].
The eigenvalues of the symmetrized irreducible polarizability for Iodine dimer (I_{2}) are reported in Fig. 1.
Results were obtained using the program `wstat.x`

of the WEST package.

**Fig. 1** - Eigenvalues of the symmetrized irreducible polarizability for Iodine dimer (I_{2}). The calculations were performed with two exchange-correlation functionals: PBE and PBE0; pseudopotentials: Scalar Relativistic (SR), Fully Relativistic (FR).

## Spectral Function

The G_{0}W_{0} spectral function of Iodine dimer (I_{2}) is computed in WEST with full frequency integration.
Results were obtained using the program `wfreq.x`

of the WEST package.

**Fig. 2** - G_{0}W_{0} spectral function of Iodine dimer (I_{2}). The calculation was performed with the PBE exchange-correlation functional, and with Fully Relativistic (FR) pseudopotentials.

## Vertical Ionization Potential (VIP)

**Legend**

- EXP: Experimental value
- FF-CD: Full Frequency integration w/ Contour Deformation
- Full: Full solution of the quasiparticle (QP) eq.
- PSP-FR: Pseudopotentials w/ Fully Relativistic effects
- PSP-SR: Pseudopotentials w/ Scalar Relativistic effects
- PW: Plane Waves
- XC: Exchange and Correlation

### References and notes

*Optimization algorithm for the generation of ONCV pseudopotentials*, Comput. Phys. Comm. 196, 36 (2015).

*Implementation and Validation of Fully-Relativistic GW Calculations: Spin-Orbit Coupling in Molecules, Nanocrystals and Solids*, J. Chem. Theory Comput. 12, 3523 (2016).

*Large Scale GW calculations*, J. Chem. Theory Comput. 11, 2680 (2015).