Running an interrupted job

Questions
#1

Hey, my 16h+ job got interrupted by windows update at night during Calculating analytic Hessian of the SCF energy for freq.

Is there any way to NOT have to start calculations from the begginig?
Here’s my input file if needed

$molecule
0 1
  S    0.0000000    1.0779892   -0.0000000
  C   -0.0000000   -0.1593867    1.3398889
  C   -0.0000000    0.5506506    2.6875695
  C    0.0000000   -0.1593867   -1.3398889
  C    0.0000000    0.5506506   -2.6875695
 Cl   -0.0000000   -0.6429519    4.0101583
 Cl    0.0000000   -0.6429519   -4.0101583
  H    0.9150537   -0.7858460    1.2682488
  H   -0.9150537   -0.7858460    1.2682488
  H   -0.9045556    1.1884038    2.7820166
  H    0.9045556    1.1884038    2.7820166
  H   -0.9150537   -0.7858460   -1.2682488
  H    0.9150537   -0.7858460   -1.2682488
  H    0.9045556    1.1884038   -2.7820166
  H   -0.9045556    1.1884038   -2.7820166
$end

$rem
   BASIS  =  aug-cc-pVTZ
   GUI  =  2
   METHOD  =  wB97XD
$end



@@@

$molecule
read
$end

$rem
   BASIS  =  aug-cc-pVTZ
   GUI  =  2
   JOB_TYPE  =  Frequency
   METHOD  =  wB97XD
   SCF_CONVERGENCE  =  8
$end



@@@

$molecule
read
$end

$rem
   BASIS  =  aug-cc-pVTZ
   GUI  =  2
   JOB_TYPE  =  Optimization
   METHOD  =  wB97XD
   SCF_CONVERGENCE  =  8
$end
#2

With respect to the frequency calculation, the short answer is: no.

Obviously you have the final, optimized geometry so there is no need to redo the geometry optimization, and if you have the old scratch files then you can use SCF_GUESS=READ in your JOBTYPE=FREQ to read in the MOs from previous job (in that case you need to invoke Q-Chem with the -save option and specify the name of the scratch file directory for that particular job). That will allow the SCF to complete in a (mandatory minimum of) two SCF cycles. However, previous work beyond the SCF (e.g., CPSCF) has been lost. Note that CPSCF is the main bottleneck in a frequency job so even if you don’t have those scratch files, you are not losing much by just pasting the optimized geometry into your input and running JOBTYPE=FREQ from the beginning.

Better checkpointing in Q-Chem is under development but we’re not there yet.

#3

Thank you very much, this helps a lot!