After booting up Multiwfn, you should load .fch file first, and then after entering the function for calculating delta_r, input the path of out/log file. Please try to reproduce the example of evaluating delta-r in Section 4.18.4 of Multiwfn manual first.

In addition,  iop(9/40=2) is not adequate. In order to obtain relatively accurate delta-r, you should use at least  iop(9/40=3).

I used the Gaussian09 output files *.log. In the route section I specified following: #t b3lyp/gen pseudo=read td=(nstates=80) pop=full gfinput iop(9/40=2) scrf=(solvent=toluene) scf=(maxcycle=250) IOp(3/76=1000001500) IOp(3/77=0720008000) IOp(3/78=0810010000).
Multiwfn successfully loaded the output files, but when I inputted the indexes of the excited states that you want to calculate delta_r, they immediately closed. The same happened when I loaded the calculation results with more simple route section: # b3lyp/gen pseudo=read td=(nstates=80) scrf=(solvent=toluene) scf=(maxcycle=250) IOp(3/76=1000001500) IOp(3/77=0720008000) IOp(3/78=0810010000).
The output file successfully was opening and calculating two years ago but now it does not do the same calculations with new and old files.
I sent the log files to the admin email and will be appreciated for helping with this issue.

Probably there is a problem in your input file, or the format of your input files is incompatible with this function.

Please upload your input file; if the file is too large even after compression, please send the file to my E-mail.

Dear colleagues,
I found some problems with electron excitation analysis especially with calculations of delta_r index and lambda index.
When the index of the excited states that I want to calculate delta_r index is inputted, the program  immediately closed without giving the results.
Does anybody find the same issue or know how to perform the mention calculations?
Thanks in advance.