Molcas Forum

Arav

Member

Registered: 2025-12-14

Posts: 2

XMS-CASPT2: ALASKA does not compute gradients → optimization does not

I am trying to perform a geometry optimization for excited state using state-averaged CASSCF followed by XMS-CASPT2. CASSCF and CASPT2 run normally, but ALASKA exits immediately without producing gradients, so SLAPAF never starts the optimization.
This is my input file

&GATEWAY
  Coord
  molecule.xyz
  Basis = aug-cc-pVDZ
  Group = Nosym

&SEWARD

&RASSCF
  Spin = 1
  Nactel = 12 0 0
  Inactive = 6
  Ras2 = 10
  CIROOT = 2 2 1
  WF, Charge = 0, Spin = 1

&CASPT2
  IPEA = 0.00
  Imaginary = 0.20
  XMultistate = all

&ALASKA

&SLAPAF
  Root = 2
  Iter = 100

Output issue:

--- Start Module: alaska ---
--- Stop Module: alaska /rc=_RC_INVOKED_OTHER_MODULE_
Happy landing, but additional module(s) requested

No gradient is produced, so the geometry optimization cannot begin.
“Are analytic gradients for XMS-CASPT2 supported in OpenMolcas 2023, or is there an issue with my input file?”

Ignacio

Administrator

From: Uppsala

Registered: 2015-11-03

Posts: 1,204

Re: XMS-CASPT2: ALASKA does not compute gradients → optimization does not

1. You need a loop from SEWARD to SLAPAF:

> do while
&SEWARD
...
&SLAPAF
> end do

2. Analytical CASPT2 gradients were introduced in August 2023, but there have been some functionality and syntax changes after, so what works with the latest version may not work with an older one.

Arav

Member

Registered: 2025-12-14

Posts: 2

Re: XMS-CASPT2: ALASKA does not compute gradients → optimization does not

Thank you for the clarification regarding the SEWARD–SLAPAF loop and the CASPT2 gradient support. I hope this information will help me move forward with resolving the issue.