From: Klaus-D. Warzecha [warzecha@cityweb.de] Sent: Saturday, August 01, 1998 5:49 PM To: hyperchem@hyper.com Subject: List Serve Archive - no traffic in June ? Dear HyperChemists, a short view at http://www.hyper.com/support/view_mail.html revealed the lack of a ListServe Archive for June so far. Is it just in preparation or was there really no traffic ? I already feared that I might have been kicked off the mailing list, but apparently everyone just spent the last two month on labwork :-) Yours, Klaus-D. Warzecha From: Klaus-D. Warzecha [warzecha@cityweb.de] Sent: Monday, August 03, 1998 12:41 PM To: hyperchem@hyper.com Subject: Your unattended mails - An apology ! Dear HyperChemists, whoever spend his precious time on answering my requests had to realize that his kindness was left unattended and his probably most helpful remarks were not answered. Please take my apologies for what might have appeared to be extremely impolite. I just had to realized that I forgot to update my email address at the hyperchem list server. As a result, all public mail was unfortunately send to oblivion. Yours, Klaus-D. Warzecha In case you might feel the need to express your anger, send your flames to warzecha@cityweb.de. I guess I have to stand it. From: Arthur Cammers [cammers@caribe.chem.uky.edu] Sent: Monday, August 03, 1998 11:36 PM To: hyperchem Subject: help with script Dear Hyper Chemists: Could someone out there in Hyperchem land send me or post the minimal text necessary to do the following in a hyperchem script: 1) Read .hin file 2) Minimize a structure in periodic boundry water using AM1 with two dihedrals fixed. 3) Minimize the structure again with a new fixed value for dihedral one 4) repeat 2) x times 5) change the second dihedral and run through fixed values for the first dihedral. repeat 5) y times. 6) write minimized structures as a function of the second dihedral. 7) write an array containing three columns Ang1 Ang2 E Thank you for your time if you decide to go for it. I am using version 4.5 for SGI. Arthur Cammers-Goodwin Assistant Professor of Chemistry Department of Chemistry-Organic Division University of Kentucky acgood1@pop.uky.edu http://www.chem.uky.edu/research/cammers/cammerscv.html From: Mei, George [gmei@corp.olin.com] Sent: Wednesday, August 12, 1998 10:30 AM To: 'Hypercube' Subject: Variance of energy by re-aligning molecule Dear Hyperchem host and users: I encountered a situation where when I re-align a molecule, I get a different energy as much as 48 kcal. I certainly expect energy is invariant under a re-align operation. I have attached the hin file which exhibit the problem hoping someone may help me pin point it. The structure is a transition state (obtained through a transition state search ; synchronous transit) of the dissociation of NO2 radical para to the -OH from a diazodinitrophenl molecule. PM3 and UHF were used through out. Single point calculations of singlet and triplet were carried out with the original file. They both yield -1793 kcal (with minor difference as expected). However, after I re-align the primary axis of the molecule to x-axis, the singlet energy changes un-expectedly to -1745.8 kcal while the triplet energy remained the same: -1793 kcal. I have tried changing the convergence limit and turning on and off the ACCELERATED CONVERGENCE switch with no avail. I am using Hyperchem 5.1 on Windows NT 4.0 with a Pentium 200 Mhz processor. <> forcefield mm+ sys 0 view 40 0.15335 55 15 0.9609374 -0.2718481 0.05193983 0.2687359 0.9613572 0.05977834 -0.06618331 -0.04348512 0.9968595 0.38858 -0.65326 -55.058 seed 0 mol 1 atom 1 - N NO - 0.8221507 0.3229545 4.599983 0.1888527 3 2 a 3 a 16 s vel 1 0 0 0 basisset 1 3-21G atom 2 - O O1 - -0.4193988 1.434617 4.231262 0.02675938 1 1 a vel 2 0 0 0 basisset 2 3-21G atom 3 - O O1 - -0.4026661 -0.3335856 5.542798 -0.08519228 1 1 a vel 3 0 0 0 basisset 3 3-21G atom 4 - C C3 - -0.4578819 -1.157792 -1.129416 -0.01036203 3 5 d 8 s 10 s vel 4 0 0 0 basisset 4 3-21G atom 5 - C C3 - 0.08085775 -1.153107 0.22893 -0.1990191 3 4 d 13 s 16 s vel 5 0 0 0 basisset 5 3-21G atom 6 - C C3 - 0.0005440712 1.341771 0.3057967 -0.1643955 3 7 s 14 s 16 d vel 6 0 0 0 basisset 6 3-21G atom 7 - C C3 - -0.5362558 1.36336 -1.121323 0.03839641 3 6 s 8 s 15 d vel 7 0 0 0 basisset 7 3-21G atom 8 - C CO - 0.4317856 0.1076513 -1.890248 0.1470326 3 4 s 7 s 9 d vel 8 0 0 0 basisset 8 3-21G atom 9 - O O1 - -0.361938 0.1165015 -3.095108 0.3647076 1 8 d vel 9 0 0 0 basisset 9 3-21G atom 10 - N NO - 1.325303 -2.457529 -1.888223 0.04067468 3 4 s 11 a 12 a vel 10 0 0 0 basisset 10 3-21G atom 11 - O O1 - -0.5794849 -2.836426 -2.456354 -0.9580773 1 10 a vel 11 0 0 0 basisset 11 3-21G atom 12 - O O1 - -0.5881319 -3.102243 -1.857873 1.065168 1 10 a vel 12 0 0 0 basisset 12 3-21G atom 13 - H H - 0.1328874 -2.05459 0.8439686 -0.306831 1 5 s vel 13 0 0 0 basisset 13 3-21G atom 14 - H H - 0.1387448 2.241705 0.9235962 -0.2389353 1 6 s vel 14 0 0 0 basisset 14 3-21G atom 15 - N N1 - 0.764782 2.537907 -1.767825 0.13489 2 7 d 17 d vel 15 0 0 0 basisset 15 3-21G atom 16 - C C3 - -0.1234603 0.1040223 0.8252262 -0.2543746 3 5 s 6 d 1 s vel 16 0 0 0 basisset 16 3-21G atom 17 - N NA - -0.2278361 3.524777 -2.295192 0.2107057 1 15 d vel 17 0 0 0 basisset 17 3-21G endmol 1 selection bond1 2 selectrestraint 1 0.000000 0.000000 0.000000 0.000000 0.000000 selectatom 7 molecule 1 selectatom 15 molecule 1 endselection bond1 selection bond2 2 selectrestraint 1 0.000000 0.000000 0.000000 0.000000 0.000000 selectatom 4 molecule 1 selectatom 10 molecule 1 endselection bond2 selection bond3 2 selectrestraint 1 0.000000 0.000000 0.000000 0.000000 0.000000 selectatom 1 molecule 1 selectatom 16 molecule 1 endselection bond3 selection REACTANT 17 selectrestraint 1 0.000000 0.000000 0.000000 0.000000 0.000000 selectatom 1 molecule 1 selectatom 2 molecule 1 selectatom 3 molecule 1 selectatom 4 molecule 1 selectatom 5 molecule 1 selectatom 6 molecule 1 selectatom 7 molecule 1 selectatom 8 molecule 1 selectatom 9 molecule 1 selectatom 10 molecule 1 selectatom 11 molecule 1 selectatom 12 molecule 1 selectatom 13 molecule 1 selectatom 14 molecule 1 selectatom 15 molecule 1 selectatom 16 molecule 1 selectatom 17 molecule 1 endselection REACTANT Thanks! George Mei, Ph.D. Olin Corporation e-mail gmei@corp.olin.com From: Carlos [riusal@servidor.unam.mx] Sent: Monday, August 17, 1998 10:48 AM To: Mei, George Cc: 'Hypercube' Subject: Re: Variance of energy by re-aligning molecule Mei, George wrote: > Dear Hyperchem host and users: > I encountered a situation where when I re-align a molecule, I get a > different energy as much as 48 kcal. I certainly expect energy is > invariant under a re-align operation. I have attached the hin file > which > exhibit the problem hoping someone may help me pin point it. > The structure is a transition state (obtained through a transition > state > search ; synchronous transit) of the dissociation of NO2 radical para > to > the -OH from a diazodinitrophenl molecule. PM3 and UHF were used > through > out. Single point calculations of singlet and triplet were carried > out > with the original file. They both yield -1793 kcal (with minor > difference as expected). However, after I re-align the primary axis of > > the molecule to x-axis, the singlet energy changes un-expectedly to > -1745.8 kcal while the triplet energy remained the same: -1793 kcal. > I have tried changing the convergence limit and turning on and off the > > ACCELERATED CONVERGENCE switch with no avail. > I am using Hyperchem 5.1 on Windows NT 4.0 with a Pentium 200 Mhz > processor. > <> > forcefield mm+ > sys 0 > view 40 0.15335 55 15 0.9609374 -0.2718481 0.05193983 0.2687359 > 0.9613572 0.05977834 -0.06618331 -0.04348512 0.9968595 0.38858 > -0.65326 > -55.058 > seed 0 > mol 1 > atom 1 - N NO - 0.8221507 0.3229545 4.599983 0.1888527 3 2 a 3 a 16 s > vel 1 0 0 0 > basisset 1 3-21G > atom 2 - O O1 - -0.4193988 1.434617 4.231262 0.02675938 1 1 a > vel 2 0 0 0 > basisset 2 3-21G > atom 3 - O O1 - -0.4026661 -0.3335856 5.542798 -0.08519228 1 1 a > vel 3 0 0 0 > basisset 3 3-21G > atom 4 - C C3 - -0.4578819 -1.157792 -1.129416 -0.01036203 3 5 d 8 s > 10 > s > vel 4 0 0 0 > basisset 4 3-21G > atom 5 - C C3 - 0.08085775 -1.153107 0.22893 -0.1990191 3 4 d 13 s 16 > s > vel 5 0 0 0 > basisset 5 3-21G > atom 6 - C C3 - 0.0005440712 1.341771 0.3057967 -0.1643955 3 7 s 14 s > 16 > d > vel 6 0 0 0 > basisset 6 3-21G > atom 7 - C C3 - -0.5362558 1.36336 -1.121323 0.03839641 3 6 s 8 s 15 d > > vel 7 0 0 0 > basisset 7 3-21G > atom 8 - C CO - 0.4317856 0.1076513 -1.890248 0.1470326 3 4 s 7 s 9 d > vel 8 0 0 0 > basisset 8 3-21G > atom 9 - O O1 - -0.361938 0.1165015 -3.095108 0.3647076 1 8 d > vel 9 0 0 0 > basisset 9 3-21G > atom 10 - N NO - 1.325303 -2.457529 -1.888223 0.04067468 3 4 s 11 a 12 > a > vel 10 0 0 0 > basisset 10 3-21G > atom 11 - O O1 - -0.5794849 -2.836426 -2.456354 -0.9580773 1 10 a > vel 11 0 0 0 > basisset 11 3-21G > atom 12 - O O1 - -0.5881319 -3.102243 -1.857873 1.065168 1 10 a > vel 12 0 0 0 > basisset 12 3-21G > atom 13 - H H - 0.1328874 -2.05459 0.8439686 -0.306831 1 5 s > vel 13 0 0 0 > basisset 13 3-21G > atom 14 - H H - 0.1387448 2.241705 0.9235962 -0.2389353 1 6 s > vel 14 0 0 0 > basisset 14 3-21G > atom 15 - N N1 - 0.764782 2.537907 -1.767825 0.13489 2 7 d 17 d > vel 15 0 0 0 > basisset 15 3-21G > atom 16 - C C3 - -0.1234603 0.1040223 0.8252262 -0.2543746 3 5 s 6 d 1 > s > vel 16 0 0 0 > basisset 16 3-21G > atom 17 - N NA - -0.2278361 3.524777 -2.295192 0.2107057 1 15 d > vel 17 0 0 0 > basisset 17 3-21G > endmol 1 > selection bond1 2 > selectrestraint 1 0.000000 0.000000 0.000000 0.000000 0.000000 > selectatom 7 molecule 1 > selectatom 15 molecule 1 > endselection bond1 > selection bond2 2 > selectrestraint 1 0.000000 0.000000 0.000000 0.000000 0.000000 > selectatom 4 molecule 1 > selectatom 10 molecule 1 > endselection bond2 > selection bond3 2 > selectrestraint 1 0.000000 0.000000 0.000000 0.000000 0.000000 > selectatom 1 molecule 1 > selectatom 16 molecule 1 > endselection bond3 > selection REACTANT 17 > selectrestraint 1 0.000000 0.000000 0.000000 0.000000 0.000000 > selectatom 1 molecule 1 > selectatom 2 molecule 1 > selectatom 3 molecule 1 > selectatom 4 molecule 1 > selectatom 5 molecule 1 > selectatom 6 molecule 1 > selectatom 7 molecule 1 > selectatom 8 molecule 1 > selectatom 9 molecule 1 > selectatom 10 molecule 1 > selectatom 11 molecule 1 > selectatom 12 molecule 1 > selectatom 13 molecule 1 > selectatom 14 molecule 1 > selectatom 15 molecule 1 > selectatom 16 molecule 1 > selectatom 17 molecule 1 > endselection REACTANT > > Thanks! > > George Mei, Ph.D. > Olin Corporation > e-mail gmei@corp.olin.com I have done the calculation with the hin file you send and using also PM3, UHF , singlet and triplet, first with the file you send and then aligning the molecule in x-axis and my reults are always -1793 I could not find the difference you are obtaining. Sincerelly yours Dr. Carlos Rius Prof of Chemistry Faculty of Chemistry UNAM Mexico From: Joel Polowin [JPolowin@idsdetection.com] Sent: Tuesday, August 18, 1998 5:46 AM To: 'Hypercube'; "Mei, George"@ftp.hyper.com Subject: RE: Variance of energy by re-aligning molecule Date: Tue, 18 Aug 1998 08:30:12 -0400 Sender: listadmin@hyper.com Precedence: bulk Reply-To: Joel Polowin George Mei wrote: > The structure is a transition state (obtained through a transition state > search ; synchronous transit) of the dissociation of NO2 radical para to > the -OH from a diazodinitrophenl molecule. PM3 and UHF were used through > out. Single point calculations of singlet and triplet were carried out > with the original file. They both yield -1793 kcal (with minor > difference as expected). However, after I re-align the primary axis of > the molecule to x-axis, the singlet energy changes un-expectedly to > -1745.8 kcal while the triplet energy remained the same: -1793 kcal. >I am using Hyperchem 5.1 on Windows NT 4.0 with a Pentium 200 Mhz >processor. I can reproduce the effect. I'm using HyperChem 5.01c under Win NT 4.0, Service Pack 3. The convergence limit is 0.01, and the iteration limit (probably not relevant here) is 50. These details may be important... Joel jpolowin@idsdetection.com From: support [support@hyper.com] Sent: Tuesday, August 18, 1998 12:07 PM To: hyperchem@hyper.com Subject: Re: Variance of energy by re-aligning molecule Dear George, The situation you feel you have encountered is in fact a common mistake made by many users with not so common structures. The energy is indeed invariant under rotation and translation! I have annotated your message to show where the percieved problem occured: George Mei wrote: > > From: "Mei, George" > To: "'Hypercube'" > Subject: Variance of energy by re-aligning molecule > Date: Wed, 12 Aug 1998 12:30:00 -0500 > > Dear Hyperchem host and users: > I encountered a situation where when I re-align a molecule, I get a > different energy as much as 48 kcal. I certainly expect energy is > invariant under a re-align operation. I have attached the hin file which > exhibit the problem hoping someone may help me pin point it. > The structure is a transition state (obtained through a transition state > search ; synchronous transit) of the dissociation of NO2 radical para to > the -OH from a diazodinitrophenl molecule. PM3 and UHF were used through Here is the cause of the percieved problem (Using UHF for both singlet and triplet). > out. Single point calculations of singlet and triplet were carried out The structure you are dealing with is a transition state, thus one may very well expect it NOT to be a simple singlet state. Since the structure is strained one does expects some unpaired spin to be present (triplet in this case). > with the original file. They both yield -1793 kcal (with minor > difference as expected). However, after I re-align the primary axis of Here I believe you have computed both singlet and triplet using UHF. Why should you expect both the singet and triplet to yield the same energy? When you have a molecule in such a strained geometry, should one expect the singlet to be favored over the unpaired triplet state? In this case the triplet should be more favored. The fact that you may have run the calculation as a UHF singlet does not guarantee that the converged wavefunction will be a singlet. This can be seen from comparing the calculation of the UHF singlet to the UHF triplet. You will see that the total energy from both calculations is (very nearly) identical (Energy= -1793 Kcal/mol). The ordering of the orbitals and their energies is (very nearly) the same. Now if you compute the singlet state using an RHF wavefunction, you will see a difference in energy i.e. -1745 Kcal/mol in your case, which is quite different from the UHF triplet energy. > the molecule to x-axis, the singlet energy changes un-expectedly to > -1745.8 kcal while the triplet energy remained the same: -1793 kcal. > I have tried changing the convergence limit and turning on and off the > ACCELERATED CONVERGENCE switch with no avail. (Here you have accidentally computed the RHF singlet energy!) After realigning the molecule repeat the calcualtions i.e. UHF singlet and UHF triplet, you will see that the energy is the same as in the case before aligning the molecule (1793 Kcal/mol). Now compute the RHF singlet energy, and you will find that it is the same as that obtained before realignment of the molecule (-1745 Kcal/mol)! Thus there is no violation of rotational or translational invariance! > I am using Hyperchem 5.1 on Windows NT 4.0 with a Pentium 200 Mhz > processor. > <> ...hin file deleted to save space... > Thanks! You are welcome. > > George Mei, Ph.D. > Olin Corporation > e-mail gmei@corp.olin.com Regards, Rajiv ====================================================== Rajiv Bendale, Ph.D., Director of Scientific Support Hypercube, Inc. Florida Science and Technology Park 1115 N.W. 4th Street Gainesville, Florida 32601 Voice:(352) 371-7744/(800) 960-1871 Fax:(352) 371-3662 From: Laurence Lavelle [lavelle@mbi.ucla.edu] Sent: Wednesday, August 19, 1998 9:29 PM To: hyperchem@hyper.com Subject: I will reply soon. Greetings, Due to office renovations I've had no regular workplace for 10 days. I have numerous emails backlogged and will respond soon. Thanks Laurence From: Joel Polowin [JPolowin@idsdetection.com] Sent: Friday, August 21, 1998 6:14 AM To: support Cc: hyperchem@hyper.com Subject: RE: Variance of energy by re-aligning molecule Rajiv Bendale wrote: > The situation you feel you have encountered is in fact a common mistake > made by many users with not so common structures. The energy is indeed > invariant under rotation and translation! I have annotated your message > to show where the percieved problem occured: I loaded George Mei's molecule into HyperChem and ran the singlet UHF PM3 single-point calculation as he described, and got an energy of -1793.15 kcal/mol. I then used Edit/Align Molecules to align the primary axis of the system with the X axis. And then, *making no changes to the settings*, I ran another single-point calculation, which gave an energy of -1745.89 kcal/mol. If I align the system with the Y or Z axis, the single-point energy is -1793 kcal/mol. Sometimes when I re-align with the X axis, the energy is -1793, and sometimes it's -1746 kcal/mol. I don't see a pattern yet for the change, but it does appear that there's something odd happening in the calculations. Joel jpolowin@idsdetection.com From: Marcio Cyrillo - pos [cyrillo@ifi.unicamp.br] Sent: Friday, August 21, 1998 12:30 PM To: hyperchem@hyper.com Subject: cristal structures Dear HyperChemists, We would like to know if it is possible to perform calculations on cristal structures using HyperChem (with ChemPlus). We have tried to do this using the chemplus module to design the cristal, but when the structure is exported to HyperChem workspace and the semi-empirical method pm3 is applied, it seems that the calculation is carried out only over the structure that is actually seen in the workspace, not on the entire actual cristal structure. Can anyone please comment on this? We appreciate any help and thank in advance. Best regards, MC/DSG. http://www.ifi.unicamp.br/gsonm From: support [support@hyper.com] Sent: Friday, August 21, 1998 5:20 PM To: hyperchem@hyper.com Cc: jpolowin@idsdetection.com Subject: RE: Variance of energy by re-aligning molecule Dear HyperChemists, Joel Polowin wrote: >I loaded George Mei's molecule into HyperChem and ran the singlet UHF >PM3 >single-point calculation as he described, and got an energy of -1793.15 >kcal/mol. I then used Edit/Align Molecules to align the primary axis >of the system with the X axis. And then, *making no changes to the >settings*, I ran another single-point calculation, which gave an energy >of -1745.89 kcal/mol. If I align the system with the Y or Z axis, the >single-point energy is -1793 kcal/mol. Sometimes when I re-align with >the X axis, the energy is -1793, and sometimes it's -1746 kcal/mol. I >don't see a pattern yet for the change, but it does appear that there's >something odd happening in the calculations. > >Joel >jpolowin@idsdetection.com Here is some information that will perhaps shed more light on the problem: I carried out a series of calculations on the molecule referred to by Dr. George Mei in an earlier posting, using the following conditions/parameters. For all the calculation presented below, the SCF convergence was set to 1.E-9, and the maximum number of SCF cycles was set to 550. I have used AM1 and PM3 to obtain the Hartree-Fock SCF energy for the molecule in question, using these settings, for both before and after alignment with the x-axis. The wavefunction was computed using UHF and RHF, I summarize my results in the tables below: Table 1 Unaligned molecule , with accelerated convergence (energy in Kcal/mol) ================================= Wavefunction AM1 PM3 ================================= UHF, S=1 E=-1777.8 E=-1793.2 UHF, S=3 E=-1777.8 E=-1793.2 RHF, S=1 E=-1694.3 E=-1718.4 ================================= Table 2 Aligned molecule (x-axis), with accelerated convergence (energy in Kcal/mol) ================================= Wavefunction AM1 PM3 ================================= UHF, S=1 E=-1777.8 E=-1745.8* (with accelerated convergence) UHF, S=3 E=-1777.8 E=-1793.2 RHF, S=1 E=-1694.3 E=-1718.4 UHF, S=1 E=-1793.2** (no accelerated convergence) ================================= In Table 1, there appears to be no problem in the final energy for both the singlet (S=1) and triplet (S=3) UHF wavefunction. Both AM1 and PM3 yield the same UHF wavefunction (S=3 even when S=1 specified). For all calculations in Table 1, the accelerated convergence option was used. In Table 2, all the calculations were performed after the molecule was re-aligned to the molecular x-axis. In trial 1, using UHF wavefunction with singlet state (S=1) selected, the energy under PM3 is indeed different! AM1 however yields the same energy as the triplet state. The same UHF singlet (S=1) calculation with PM3, yields the same energy as the triplet only if "accelerated convergence" is turned off (last entry of Table 2). This implies that within the PM3 model, choosing UHF singlet (S=1) may converge to some spin state that is higher in energy than the true triplet state. The RHF singlet yields the same energy for the molecule before and after alignment. From this one can conclude that the use of DIIS ( SCF convergence accelerator) may introduce slight numerical differences that result in the intermediate state (E=-1745Kcal/mol) being found instead of the lower triplet state with E=-1793 Kcal/mol. A look at the two UHF wavefunctions (with starting S=1) with energy E=-1793.2 and E=-1745.8 Kcal/mol, should show what distinct states the wavefunction correspond to. This should explain what is occuring in the situation referred to by Dr. Polowin and Dr. Mei. Any comments welcomed. Regards, Rajiv ------------------------------------------------------ Rajiv Bendale, Ph.D., Director of Scientific Support Hypercube, Inc. Florida Science and Technology Park 1115 N.W. 4th Street Gainesville, Florida 32601 Voice:(352) 371-7744/(800) 960-1871 Fax:(352) 371-3662 From: Laurence Lavelle [lavelle@mbi.ucla.edu] Sent: Friday, August 28, 1998 6:07 AM To: amber@cgl.ucsf.edu; chemistry@infomeister.osc.edu hyperchem@hyper.com Subject: Amber 5 as back end with HyperChem 5 as front end Date: Thu, 27 Aug 1998 21:58:43 -0700 Sender: listadmin@hyper.com Precedence: bulk Reply-To: Laurence Lavelle Anyone tried using HyperChem 5 for data analysis of Amber 5 output? Any suggestions or good or bad reasons to do this. Laurence From: Haberhauer Georg [Georg.Haberhauer@arcs.ac.at] Sent: Monday, August 31, 1998 12:49 AM To: 'hyperchem@hyper.com' Post-Doctoral Research Position Modelling of Sorption of Organic Compounds at Clay Mineral/Aqueous Solution Interface A post-doctoral position is available for 2 years (extendable to 3 years) in the field of modelling adsorption processes in soil on a molecular level. The work will involve a wide spectrum of computational methods ranging from ab initio and density-functional methods to force field applications. The investigations will be carried out in a multidisciplinary environment via a cooperation between the Institute for Theoretical Chemistry and Radiation Chemistry of the University of Vienna and the Austrian Research Centers in Seibersdorf near Vienna. The position is financed by the Austrian Science Fund. Start of the research work: as soon as possible. Sound working experience with the application of quantum chemical methods and with UNIX workstations (Linux) is required. Send your CV to Hans Lischka Institute for Theoretical Chemistry and Radiation Chemistry Waehringerstrasse 17 A-1090 Vienna Austria E-mail: Hans.Lischka@univie.ac.at Fax: +43-1-4277-9527