The United States has indicated to South Africa in clear terms that it is willing to "open a new chapter" in bilateral ties in exchange for cooperation on combating Soviet influence in southern Africa and on attaining an "internationally acceptable" solution in Namibia, according to State Department working papers.

U.S. officials confirmed basic information contained in several of the briefing papers, which were drafted by high-level U.S. officials in preparation for the recent visit by South African Foreign Minister Roelof (Pik) Botha. The documents were made available to The Washington Post by Randall Robinson, the executive director of TransAfrica, a black-oriented lobbying group on African affairs that consistently has opposed South African racial policies.

One of the papers suggested that if the South Africans cooperate on an "internationally acceptable settlement" of the problem of Namibian independence, the United States can "work to end South Africa's polecat status in the world and seek to restore its place as a legitimate and important regional actor with whom we can cooperate pragmatically."

Secretary of State Alexander M. Haig Jr. was advised by his top aide on Africa that the administration should respond to South African cooperation on Namibia -- a territory South Africa continues to contral under an expried League of Nations mandate -- with "small but concrete steps such as the normalization of our military attache relationship."

The two countries have greatly reduced their military representations -- to one attache each -- since Pretoria accused three American attaches of taking aerial photographs of secret installations in April 1979.

A recurring theme in the documents is the role South Africa can play in helping the United States counter Soviet influence in such places as Namibia and Angola. The new chance for improved relations, as one of Haig's advisers put it, "represents an opportunity to counter the Soviet threat in Africa."

State Department officials reflected awareness that their talks with the South Africans had potential pitfalls. Assistant Secretary of State-designate for African Affairs Chester A. Crocker advised Haig that "South African truculence (which can be coated with great charm) is compounded by the fact that, as an international pariah, the country has 'had no meaningful, balanced bilateral relations in recent memory.'

"Thus," Crocker continued, "the South Africans deeply resent being treated as an embarrassment and are not used to the give-and-take of pragmatic relations. If the South Africans still want to vent their frustrations, I fear you will be subjected to Pik's rhetoric. Thus, it is in your interest to take control of the meeting from the beginning."

Although there have been broad hints of a shift in the Reagan administration's public posture toward South Africa -- particularly compared with the Carter administration's approach of cooperating more with black Africa and confronting South Africa on its racial policies -- the background papers provide some of the clearest documentation to date of how far the United States is willing to go to help the internationally isolated Pretoria government attain some degree of respectability in the world.

In a background briefing for reporters on May 16 after Both's talks here, the Reagan administration announced that it was prusing a policy of "constructive engagement" with the South Africans, rather than the previous policy of "confrontation."

Reporters were not given details of impending changes in the U.S.-South African relationship.

By aligning itself, however marginally, with South Africe, the United States is taking a calculated risk that it will not completely alienate many Third World countries, particularly in black Africa, where Pretoria is viewed as a pariah because of its official policy of apartheid, or institutionalized separation of the races.

Nigerian President Shehu Shagari, on a recent state visit to Britain, warned the United States against tilting its policy on Africa toward Pretoria or helping the South Africans back the rebel forces of Jonas Savimbi in Angola. Shagari said it would be "very unwise" for Washington to back rebels in a sovereign African nation. Nigeria is the second-largest supplier of foreign oil to the United States, supplying 1.2 million barrels per day.

An American shift toward South Africa also confronts head-on key issues such as Namibia, military cooperation and exports of strategic minerals, such as enriched uranium.

The State Department papers reflected the thinking of senior officials on the U.S.-South African relationship, officials said. Robinson said he obtained the papers from a State Department employe, and U.S. officials confirmed their authenticity. Robinson would not reveal his source.

Robinson said he passed on the documents because he felt that the United States is "moving into a defacto alliance with South Africa in exchange for no clear commitment on South Africa's part" and that there should be a wider public debate on the issue.

The U.S. view of the new developing relationship is that it is a more pragmatic approach to dealing with the South Africans, that the United States will be in a better poisiton to pressure the South Africans for change if it shows willingness to support positive movement for change.

According to the paper prepared by Crocker for Haig's talks with Botha, the United States sees its new relationship as being "based upon our shared hopes for the future prosperity, security and stability of southern Africa, consturctive change within South Africa and our shared perception of the role of the Soviet Union and its surrogates in thwarting those goals."

The U.S. position was that although Washington and Pretoria "may continue to differ on apartheid,"the U.S. "can cooperate with a society undergoing constructive change."

African diplomats interviewed here stressed that as long as South Africa continues it policies of apartheid, they cannot cooperate with Pretoria, and they said they were watching closely the formulation of the new administration's policy on southern Africa. The Africans are also concerned that the United States would abandon its support of U.N. Security Council Resolution 435, which it and the Africans currently accept as the basis for Namibian independence.

According to the May 16 briefing, the United States and South Africa did not fully achieve a meeting of minds on Namibia.

Nevertheless, at a news conference upon his return to South Africa, Botha hailed what he called a new American realism on the Namibian question.

"All round I found a much greater grasp and understanding, the ability to look at South Africa in a different light, to see the importance of the Cape [of Good Hope] route in a clear way, our strategic minerals and other things."

Another document left behind by the South Africans said they would be prepared to secure U.S. access to critical minerals and naval facilities, and generally protect U.S. financial and trade interest naval facilities, and generally protect U.S. financial and trade interest in the region, if Washington recognized that there are "no shortcut solutions to the question of the exercise of political power in South Africa."

In another paper, a secret South African summary of the sticky nuclear relationship between the two countries, Pretoria asked Washington to review its policy, established under the Carter administration, of forbidding export licenses for enriched nuclear fuel to South Africa as long as South Africa does not adhere to the Nuclear Nonproliferation Treaty or accept international safeguards at its research facilities.

State Department officials said the United States has not changed its position, although discussions are continuing on the problem. There has been a four-year impasse over U.S. refusal to ship fuel under terms of a South African contract with the Department of Energy.

Overall, U.S. officials emphasized that the South Africans did not obtain all that they thought they might from the U.S. side during Boths'a visit, but, as one source put it, "They haven't gotten beaten over the head repeatedly with posturing, either."