I want find the free energy change, when we convert lj fluid (single site)
to real fluid (any solvent). I am planning to use thermodynamic
integration.

H=h1*(1-lamda)+h2*lamda

where h1 is lj fluid Hamiltonian and h2 is hamiltonian of solvent.

is it possible to compute free energy change directly from lammps (using
compute ti) ?

I want find the free energy change, when we convert lj fluid (single site)
to real fluid (any solvent). I am planning to use thermodynamic
integration.

H=h1*(1-lamda)+h2*lamda

where h1 is lj fluid Hamiltonian and h2 is hamiltonian of solvent.

is it possible to compute free energy change directly from lammps (using
compute ti) ?

have you looked up in one or more papers, what would be needed to
perform this kind of calculation?
if yes, what does the LAMMPS documentation on compute ti (and related
commands) say about this?
did you find all the pieces necessary?

The objective in this case is finding the free energy of the solvent.
I am taking Lj fluid as reference since i can compute free energy of it.
now i want to find the free energy change when we convert lj fluid to
solvent. to do this will compute ti help me along with fix adapt?

but from documentation i can see that converting weak fluid to completely
interacting fluid compute ti is help full.

I want to know will compute ti along with fix adapt helpful for me in this
case ?

if so can you please help me how can i do that ....

The objective in this case is finding the free energy of the solvent.
I am taking Lj fluid as reference since i can compute free energy of it.
now i want to find the free energy change when we convert lj fluid to
solvent. to do this will compute ti help me along with fix adapt?

but from documentation i can see that converting weak fluid to completely
interacting fluid compute ti is help full.

I want to know will compute ti along with fix adapt helpful for me in this
case ?

if so can you please help me how can i do that ....

if you want help, you'll *first* have to do what i have asked you
about and which you have neglected to answer, i.e. figure out and
understand the theory behind the operation you want to perform and how
this would be possible to do *at all* with an MD code. instead you are
essentially just rewording your original question.